Workshop, Materials, and Tools
A properly equipped and maintained workshop will enable the builder to produce a high-quality product! This page will show some of my workshop setup and tools. It may be a useful reference for someone else setting up their own.

I will also provide some information here on the materials I am using. The plans epoxies, glass, and some of the foams are difficult to acquire in New Zealand (The nearest Aircraft Spruce warehouse is 11,261km away). I have substituted in some cases, after careful research. In other cases I have absorbed the cost of shipping to import the specified materials.
Materials (some non-approved alternatives!)
EPOXY
The only plans approved epoxy available here is West. It has the poorest properties of the approved epoxies, and tends to cure quickly when warm, even with the slow hardener (I have multiple lumps of exothermed epoxy to prove it!).
There is a lot of boat-building in New Zealand, with a number of high-performance specialists, thus there is a demand for high-performance epoxies, too.
I researched what epoxies were readily available, and obtained data on these where possible.  (At least once I enquired about a particular resin that was advertised on the website only to be told that it isn't available here!) Some epoxies specs are difficult to obtain in any useful detail, and so were eliminated from consideration.
I settled on Adhesive Technologies ADR-246TG with ADH 28 hardener. It provides specs similar to EZ-poxy, and much better than West.
ADR246 requires a post-cure to 50deg C to develop full-strength, which is not a big deal, and will also provide a nice high TG (highest of any epoxy I compared).
It has low viscosity and wets out very easily. A brief application of heat from a heat gun makes it flow even easier, to help squegee out any excess, keeping my epoxy/glass ratio optimal.
Mix ratio is 4:1 by weight, so easily achieved with a simple set of digital scales (I made up a ratio chart for quick reference as well)
It cures slowly at low to mid temperatures, so plenty of working time. Then I erect my heat tent (see also on this page) and raise the temperature to obtain a good cure. I completed both sides of the instrument panel in one afternoon, by allowing the first side to cure quickly under higher temperatures, then flipping and laying up the other side. Simple to do, and the best of both worlds.
I can get the resin in 20l containers (which I can simply screw a tap into for dispensing), and hardener in corresponding 5l lots.

As this is a non-approved material, please do your OWN research before considering using it yourself.

Conveniently, Adhesive Technologies is also the NZ distributor for West Systems, including fillers, so I can tack on micro / flox etc to my epoxy order and combine shipping. In fact, they have manufactured West epoxy here for decades under license, and more recently developed their own range of improved resins, of which ADR246 is one.
All my interactions with the company so far have been very positive, and I will continue to use them unless I discover a very good reason not to.
GLASS
The plans specified glass is only available here if imported. There is am importer that imports bulk Hexcell materials, but only sells in lots of 600yds or so. There is also an Aircraft Spruce distributor that can import basically anything from that catalog. Their markup on the products exceeds any savings achieved by their bulk imports.
I found the most economical way to obtain the required glass is to buy from Aircraft Spruce directly from the USA. My first order was enough glass (BID and UNI) to complete the tub. It arrived with the box torn and minor damage to a small area of glass, the rest was OK, so I accepted it. Wasn't too pleased when the delivery truck mowed down the letterbox and damaged a retaining wall on the way out, though (and failed to take any responsibility for the cost of repairs). Bad form, Mainfreight!

There are other supplies of fibreglass in New Zealand, of course, but I have not found any to be closely equivalent that are also cheaper than importing the specified stuff anyway.
I may use some alternative reinforcements in non-structural areas if it makes economic and performance sense. I plan to create custom carbon-fibre cowls, for example; no need to buy from a USA supplier if an equivalent and more economic source can be found elsewhere. Shipping from the USA is EXPENSIVE!
FOAM
I have substituted PVC foam for Clark foam in the fuselage. Gram for gram (or ounce for ounce?) it has superior properties. Plus, I couldn't find any source of Clark foam that didn't have to come from overseas. 
For the IP, F-22 and F-28, PVC-250 was the option that exceeded Clark in all respects, however, it was not available at the time. PVC-200 was substituted, and still has superior properties in most respects, and isn't far below in the remaining properties. Plus, it's 20% lighter! I have read of a Long-Ez whose fuselage bulkheads were made from PVC-200 and has been flying with no issue. I would not expect any, given that the properties are so close, and often better.
The company I sourced the PVC foam from only sells in complete sheets (and not in the sizes expected by the plans!) so I ordered as close to the required areas I could. I will have some extra of the lesser used thicknesses.

Blue styrofoam is available for the wings, though it seems it is very slightly higher density.
I'll probably substitute out urethane, don't much like the crumbly stuff. I don't mind spending a little more time forming better foams to create a superior product.
WOOD
Birch ply in the required thickness was found, but only in a full-sheet. So I can build 4 or 5 firewalls. :-)

Spruce is altogether another story, however. No local source, but there is an importer only 2.5 hours away. But getting it that way, in the small quantity I need is expensive, even when combined with the order requirements of an all-wood builder. 

Nat has stated (I found this in the mailing list archives) that the spruce longerons are primarily for forming the desired shape and providing something you can use as a hardpoint for various things. It is not structurally critical. He also approved simple repair of a snapped longeron, so joining pieces is not considered to be a problem, either. See where I'm going here?

Some builders (notably in Australia) have substituted hoop pine, but I failed to find an economical source of that, either. What I did find was BS1088 marine certified gaboon ply. It has similar density and strength properties as spruce but is a sheet of ply, rather than strips or lengths.

The plan is to cut the gaboon ply into strips of the appropriate width, and laminate strips together as needed, to create the thickness required. This is basically what is done forming the upper longerons anyway, I will just have plies of ply! Triangular strips will be cut from square on a bandsaw.
The result, by my estimations, should be at least as strong as per-plans, and far less expensive. I will need to be careful with orientation with consideration of splitting plies, but this is true to some extent with the layers of spruce as well.