My loading bench is an drafting desk. I made a top out of 3/4" plywood. Out of a 4 x8 sheet you can get a 3' x 5' piece a 4' 'x 3' piece, and a 1' x5' strip so I laminated the 3' x 5' with the 3' x 4' piece and 3' of the 1' x 5' piece to get a 1-1/2" thick 3' x 5' plywood top. Then I glued (contact cement) white plastic laminate onto the plywood top and edge banded it with 3/4" oak. Makes for a stout top, not terribly expensive.and it looks pretty decent.
Another option is do a google search for finger jointed maple butcher block counter tops. I think you can get finger jointed maple tops up to 1-3/4" thick pretty much any size you want.
If you want really stout - go find some 3-1/8" x 12" glue laminated beam - or whatever depth works to get your top depth right, glue or biscuit joint lengths together and get a 3-1/8" thick top.
I made a work bench for my shop out of some 5-1/8" x 16" glue lam beam - cut an 18' length in half and I have a great 5-1/8" x 32" top about 9' long.