As one of you recently pointed out, there’s quite a few inexpensive trestle options out there, and you can get whatever sized top you want from a glass shop or hardware store.
On the left, is Urban Outfitter’s Sawhorse Table Legs, which at $38.00 for a set of two is a pretty good deal, and actually less expensive than the sawhorses on the right. However, the ones on the right are ‘real’ sawhorses, so they’re probably a bit more sturdy as well as adjustable. I actually used these yellow sawhorses as a work table base in my office/studio when I lived in Houston. It’s hard to tell, but from the side these sawhorses actually have a little Prouve-ish feel, or at least that’s what I thought of them (it’s the angled steel in a bright color, I think). If you don’t mind an industrial-edgy look, they do the job wonderfully and will hold up well over time, either in your studio/office space or in the garage for odd jobs.