Ok, wow, thank you all. :embaresse
It's pretty simple construction. It started at 13/16, probably ended around 5/8. I put a 5/16 recessed plywood backer under it. 14" square (give or take). Didn't bother to do much finishing on the bottom side because I knew I'd be putting the felt on the bottom.
One can never have enough clamps.
Simple process if your tablesaw is a true 90 degrees. Rip your stock to 1.75" on your tablesaw, cut to 15.5" lengths using a miter box (so as not to change the fence setting on the tablesaw). Glue and clamp a couple pieces at a time, once all eight pieces are together and the glue is cured, cross cut the 1.75" on the tablesaw, flip every other piece, glue and clamp. The gluing/clamping requires patience because you cannot unclamp prematurely. Also - I'm using gorilla glue on these things (unless someone knows of a stronger glue that fills gaps just as well).
I might add, if the fence on your table saw is bowed or damaged, you're going to run into problems in the finishing stages once everything is unclamped. If you cannot get a true 90 degrees on your table saw, your board will be cupped when everything is finished, requiring a good deal of time fixing with a 48" belt sander or one of those drum sanders like FredP has. Don't ask me how I know all of this
Finely tuned quality tools will get you a much better (and faster) job than my tools can do. I've been hinting to my FIL about wanting a new tablesaw for Christmas :gar-Bi