Looking for sources for desk ideas  

You can
certainly start with a "flush" door (a hollow-core slab about 1 3/8" thick, various widths by 80" long, readily available with a birch veneered face or in dark brown smooth Masonite). This makes an excellent starting place: stiff and light, with solid material an inch or two along each edge to fasten hardware to. Look in your local building supply place. . .

door is a good start - 4 years later i'm still with it
however I bought a solid door for 5 dollars at a thrift store that carried such an item (a lot of thrift stores wouldn't accept used doors as a donation and as a consequence you wouldn't be able to buy one)
I used to have the whole door as my desk and it was a huge, great working space, but a little too large for my needs, and moving around and such, I decided to cut the door down and what I was left with was: http://www.flickr.com/photos/andyallen/44577825/in/set-979353/
I really like my saw horses. They are adjustable, foldable, weight a ton, and I like the flexibility they afford but they don't look like a crappy, or cheap overpriced one. I have a yellow pair of saw horses as well which I bought at home depot. I bought these black ones at Lowe's - besides the paint they seem the exact same to me.
http://www.flickr.com/photos/andyallen/44577825/in/set-979353/

Long and honorable tradition
As I understand it, for most of history, tables were
just this: a couple of trestles and a loose panel,
easy to knock down when you needed the space
for some other purpose or had to escape marauding barbarians. When did the attached-
legs thing become standard? Anyone?