I read something somewhere (can't remember where I'm afraid, but one of the tech/IT sites) implying that, due to some new development, SSD was about to fall in line with Moore's Law and we are likely to see affordable high-capacity drives fairly soon, e.g. 10TB is likely to be feasible. About bloody time!
Let us hope that you are forced to purchase 10TB super fast drives in pairs with the proviso that one of the pair is used for backup