I am looking to buy a treadmill to make a treadmill desk at home. As a writer who sits at my computer for 15+ hrs/day & eats continually, this would make a HUGE difference in my life (as in, my *kitten* would no longer be so HUGE)!

I can't afford one of the pre-fab treadmill desks so I am looking to rig up a redneck version - just put the treadmill up to the desk & put a box on the desk to raise my computer so I can stand.

I've seen a lot of lightly-used cheap treadmills for sale on Craig's List but I am not certain which ones are ideal for the job. Anyone had any experience with treadmill desks & have some tips on what to look for/avoid? I have read the do-it-yourself treadmill desk websites, so I know what they suggest.