I would be reluctant to put anything bigger than 10 gallons on a piece of furniture that wasn't specifically desgined for holding the weight of an aquarium. Even a 10 gallon tank I would be cautious where I placed it. A dresser almost certainly wasn't built to support a 45 or 60 gallon tank. 45 gallons of water alone weighs over 370 pounds, and that's not taking the weight of the tank or substrate into account. Add the tank and the substrate, and you are easily over 400 pounds.
I would not bother doing a custom tank for the size you're interested in. There are several common tank sizes that fit your needs. The 30 breeder, 40 breeder, 50g, and 65g are all 36"x18" with 12", 16", 18" and 24" heights, respectively. Although the increasing height doesn't really increase the fish load you can have (~54") - the surface area is constant - it just makes the tank more appealling to view, at least in some people's views. IMO the 40 breeder has the most appealing ratio of length to height of the 4 listed.
If you want to do some custom work, make a custom dresser, to replace your existing one, that can carry the weight. Getting a nice wood stand would cost you more than the tank. It's not too hard to make a pretty robust DIY stand, although making dresser drawers would give me some trouble.
Yes, it is a different tank! A normal 30 gallon tank is 36 x 12 x 16 high. For breeding you need more floor space so a 30 "breeder" only 30" long x 18" deep (to the back) & just 12" high.