I think I'm going to go for it. I'll watch how I feed it, and how it gets along with the other fish I have. If it needs a bigger tank sooner than I think, I'll work something out for sure.
I just recently bought a 55 for my GT. So I'm a bit short on cash right now. But if I need a larger tank in the future (summer-fall) I'm going to consolidate our two 10gallon goldfish tanks into my 38, move the fish from the 38 into the 55 and the (then new) 75. I have a plan, if I really do go through with this. I'm going to the LFS tomorrow.