I would say its possible, also possible to keep other types of tangs, however, you need to be responsible enough to determine if there is any stress involved with the size of your tang. If it grows and grows and shows signs of needing a larger place to swim then, you should be able to swap, donate, or do something to give it a better home and go to a smaller tang once again until it grows.
I have a 90 but have never placed a tang in it. I just feel they need a larger tank of 5 feet. Not to say that the temptation isn't there, and some day I just might break down and get a tang, but if I do I'll follow my above advise.
Thomas