I've had great luck building woodworking bench tops out of lengths of
professional laminated 2x4 glulam. Mine is 50" long as I have a small shop and I
installed 3 vises on it including a home made leg vise made with guides of 1/2"
black pipe and pipe caps and a vise screw of course. It actually is my favorite
of the vises. I got the glulam free off a contractors scrap pile as it
apparently was the cutoff from a support beam in the house he was building. At
50 inches it was too small to use anywhere else in a house. This thing is heavy
and about 20" wide and 3 1/2" thick. I put 4x4 legs on it without needing an
apron as there was enough thickness to mortise them into the underside. I cut
out openings appropriate for my pattern maker's vise to mount and a big, old,
beefy Columbian vise on the other end. Leg vise too as I said. And I could put
dog holes anywhere and many of them. The dog holes and the 3 1/2" top thickness
also allows use of the J shaped type of clamp that fits in a dog hole and can be
so handy.