So, process for this piece
, overall a bit under 3 hours in PS CS3. I had a go at working pretty much entirely on one layer here, and found it pretty fun, sort of keeps you on your toes a bit and you end up with a nicely complex image when things start getting overlaid a couple of times.
Textures mostly from cgtextures.com, aside from a couple of photos I took myself, and the brush I used came from ~leventep
's brush pack, so check that out.