I've looked at commercial folding sawhorses - and actually own one metal one. It's nice, but at about $35 a pop, they're not cheap and they're not light at about 20 pounds each. In addition, depending on the height that they're set to, you can't fold the legs up beneath the cross-rail. They do, however, support a HUGE amount of weight - 1200 pounds! Most of "sheet metal" sawhorse designs I don't much care for and they just seem a bit wimpy, actually.
I don't much care for the plastic sawhorses that are available - they're on the heavy side, they flex a bit and they're also not inexpensive. I also have a bit of a problem with the idea of making more plastic things.
A gentleman by the name of Greg Nolan who is active in the WCHA and at the WoodenBoat Forum suggested some plywood knock-down designs that look very nice, really. The sad part is that plywood has gotten fairly expensive.
I decided that I'd give a try at designing some of my own. I wanted them to be inexpensive, quick to make, stable, light-weight and easy to store. Because we're not holding up a large amount of weight with the boats we're building, that wasn't a huge concern. We also don't need particularly tall sawhorses. Here's what I came up with:
These are 28" tall, 24" wide and while I haven't weighed them yet, they're very light.
They fold down flat - as you can see in the image below.
As for materials? To make 2 sawhorses, you're looking at two 2x4's worth of material (with leftover material!), 32 deck screws, four bolts, 12 washers, 4 nuts, four feet of nylon line and a bit of glue. They are actually strong enough for me to sit on, so I'm pretty pleased with the strength. When folded, the top is at an angle which allows them to be hung on a wall with a French cleat - clearing floor space.
I'll post a how-to later this week with a drawings, a material list and cost breakdown.