Well...I have this one, but I'm not really sure it's anything like what you want and it's kinda pricey.
Since you're going to have it on a stand next to the show tank, I think the easiest route would be to buy another aquarium and have it drilled to your specs. Ideally, the fuge will be higher than the main tank so water can be pumped into it and drain back into the main tank. You could light it with a PC
fixture...actually, you could make it look really nice with a bit of planning. JMHO
I'm thinking what you're going to find, with most of the prefab fuges, is that they are either HOB
or designed to go underneath the main tank.