When designing a table saw crosscut sled, I decided that I wanted a large crosscut capacity, a sliding fence and a way to clamp the work to the sled. This single-runner sled is 32" deep x 26" wide and was easy to build. It will carry panels up to 30" wide, with a 24"-clamping capacity. The fence can slide to align with the saw-blade edge of the sled for maximum workpiece support, or it can be slid out of the path of my blade guard. The T-slots in the fence also allow for attaching adjustable stops.
The aluminum extrusion fence is straight and flat, and attaches to a wooden support with three T-bolts (sometimes called toilet bolts) through the support into a channel in the fence. Knobs on the end of the bolts allow side-to-side adjustment. I bought the 1-1⁄2" x 3" aluminum extrusion from 80/20, through the company’s e-Bay store (stores.ebay.com/8020-Inc-Garage-Sale).
To accommodate the hold-downs, I epoxied two 24"-long T-tracks into grooves I routed in the 5⁄8"-thick Baltic birch sled panel. Setting the T-track 1" away from the fence allows clamping of 24" panels from the opposite end. Also, make sure to run the groove an inch or so past the end of the track to allow insertion of the hold-down T-bolt into the track. The hold-downs, knobs and T-track are commonly available from various woodworking mail-order supply houses.