Thanks 8-Ball. I noticed your post the other day on xtremesystems.org. Good to see someone setting people straight about metals and conductivity.
I'll look through their forum for more ideas. Right now though I'm leaning towards using a converted Maze Classic:
http://www.dangerden.com/images/MAZE2/MAZE2_large.gif
Its got surface area, narrow channels, and I already have one so its free

Hopefully oil won't be too big a problem.