Check the Home-ly Depot or whatever you have locally and obtain a damaged solid core door. They can't use dinged ones in houses, so they sell them for a few bucks. I think I gave $15 for my last one. It has a tiny ding on the back edge, out of sight. These make a good, flat base for a building bench. There is a neat way to make a fuselage jig so your fuses won't resemble bananas. I'll run down that link for you in a minute.

In any event, the flatter, the better.
Kelvin

PS Here's an interesting link I had forgotten about:
http://modelinghints.homestead.com/WorkSurface.html

Ah, here it is. One of the more important tools to have:
http://webpages.charter.net/rcfu/Con.../FJConstr.html