Bamboo frame!

what do you mean by sliding dropouts? I found some stainless steel track ends for about £25, I am still deciding whether or not to go for it.

I just ordered my bamboo from the bamboo bicycle project workshop which was almost certainly overpriced... it hasn't arrived yet, but I really just wanted something that was guaranteed and treated. I'm not too sure which species it is, I'll take pics when it arrives.
I bought loads of epoxy, 1kg of the 105 with 0.2kg of the hardener. I am the sort of person who will end up needing it again though so that's ok.

Something not entirely dissimilar to these:

Pros:
Set and forget chain tension - can pop wheel in and out without needing to redo it
Disc brakes are a possibility for SS
Can get the wheel very close to the seat tube without having trouble getting it out (horizontal dropouts and trackends may require you to deflate the tyre - something to watch out for (I fucked it up)).
Can easily replace the sliding plates if you muck em up somehow, or if you decide you want gears / Rohloff etc.

Cons:
Expensive
Heavier
More complicated

£25 for stainless track ends sounds alright; I think stainless is worth the significant price hike on bits that will never paint well. I get all my framebuilding parts from Ceeway.

The amount you paid for bamboo is fair when you consider it'll be properly treated and hand-picked for the purpose. I'm taking a bit more of a punt because I'm cheap. Also I'm experimenting with thinner tubes filled with foam, could be interesting.