In short 54" high with a custom pool installer you can get at most 5' feet of total depth.
The standard size for depth in an above ground pool is 52" high. You will lose approx. 6" of water between the skimmer and the base under the liner. This gives you a true 4' feet of water. Other pool depth options are 48" pools (can be hard to find anymore) and 54" the new style deeper pool. Not that you gain any more than 2" over the standard size of 52".
Custom above ground swimming pool installers can put in a dish (deep center in a round pool) or a hopper(deep end in a oval pools) up to 12" deep.
I learned this from my salesman at www.builtrightpools.com in Philadelphia PA. If you are in the area I would highly recommend them for an installed pool package.