I think the 10' x 30" base works very well. I have seen an awful lot of burms in 8' x 2' cages that seemed just a bit cramped, although the snakes seemed fine.
The extra 2 feet of length and 6" of depth really seems to add a lot. The Russian/Finnish Birch plywood is not absolutely necessary to build such a cage, but you'll waste a lot less material by using it. And the quality/cost factor is hard to beat. Last summer I could get 5'x5' panels in 1/2" for $21 and I live in an area where such supplies are expensive.
You'll probably want 3/4" for such a large cage.
I also like how it's relatively smooth compared to other similar priced plywoods. That makes finishing much easier regardless of what you use.
I have heard of this wood showing up at Menards but not at Home Depot or Lowes. Your area may be different. I have to go to a wood-working supply store to buy it.
The AGA silicone is fine but not absolutely necessary. Any 100% silicone will work.
Regarding epoxy or other finish, that really opens up a can of worms, so to speak. One thing I don't recommend is the deck paint or any other exterior finish as recommended on albinoburmese.com. Too many reasons to list, but I don't recommend them.
With a linoleum floor you don't have to be quite as choosy for what you use on the walls. In fact, you could even use linoleum on the walls as well. I think some of the faux-tile vinyl floorings would look great in a snake cage. I would still seal the walls and floor with something before applying it. I think Bighurt mentioned that in his reply or in another post and I agree.
I think first you need to decide if you want a clear or solid colored finish. Or do you want the pattern of a vinyl flooring on the walls as well.
For a burmese I would use one of the following on the walls, assuming a durable floor was already in the plans (in no particular order):
1) Vinyl flooring
2) Vinyl film (as used in the graphics industry)
3) Envira-Poxy, a waterborne, two-part clear epoxy from Kelly Moore.
4) BonaKemi Traffic, a two-part waterborne floor finish.
I would NOT use:
1) Oil-based polyurethane, despite it's excellent protection for the cost. The extended offgassing makes me uncomfortable.
2) Any exterior finish, as already mentioned.
One last thought regarding plywood and finishes. If you cannot find the Russian birch plywood or the prices have gone up, I have another suggestion. There is a company called Nova that makes a plywood that comes with a prefinished UV cure epoxy. The coating is said to be incredibly resistant. You can even scrub it with acetone to remove glue or other adhesives that leak onto it.
It is expensive but ends up costing less than buying plywood and finishing it with epoxy yourself. But the 8'x4' panel size may not be ideal depending on your exact goals for this project.
You'll have to find it locally, as having just a few sheets shipped in will be much too expensive.
Regarding cost, I'm horrible at such things. I tend to have a lot of misc. things laying around so I don't have to go out and buy them specifically for these projects. Things like screws, paint brushes, etc. I usually even have caulk or glue leftover from other projects. It's the little things that add up.
I suspect you could do it for $300.
