I think that you would be just fine putting a bigger tank on that stand if you put a 1" piece of plywood on it. I could hook you up with 2 - 4' pieces of 2" x 2" x 1/4" angle if your worried about the over hang.
What size of tank would you be looking for? I have a 120 gal 4' x 2' x 2' Oceanic tank here.
