The Fish Hotel aquarium is basically just a regular fish bowl that looks like a hotel and they are stack-able. They make for an interesting display in your home, and there are many other unique fish bowl designs as well.
Shown here is the Umbra Fish Hotel. They look good as is, but you can also paint them if you want to. They can be stacked up, and they measure 7.5 x 7.5 x 8 inches.
Plenty of good customer reviews, as most people seem satisfied with this product. Comes as a neutral white color that will work with any room's decor, but you can also paint it however you want.
Some people have mentioned that it may be too small for a Beta fish, but others have also responded suggesting that it is fine if you do proper research on raising your Beta fish. When I first saw this product, I thought it was a cool little structure with separate rooms for your fish to go in and out of, apparently not. It is still cool though.