A few brands come to mind, I like Innovative Marine, I think Waterbox, Cade, UNS, JBJ, etc. You could also add an overflow to almost any standard tank. Were you looking for a stand and sump too, or just the tank and overflow?
OK, you want an internal overflow tank? That has the overflows inside the tank, but can be push up closer to the wall behind the tank. Do you need a stand and sump and all the gear, or just the tank?