I still don't understand what you're claiming is wrong with XOR. As I understand it, the XOR of two secure hashes should be at least as strong as each one. Of course you can find ways to deliberately come up with a broken scheme if you really want to do something spectacularly dumb (like XORing a variation of the same algorithm with itself...), at which point the problem isn't really XOR, but assuming you're being reasonable and showing some sense in the process, the likelihood of someone somehow finding an exploitable correlation between them without breaking either one should be astronomically small to not even warrant a second thought.
Just as a mental exercise (im no expert) how about. GoodHash=HF(input) + HF(reversed-input)
Your final hash value will still be twice as bjg yes, but reversing the input should yield a different result ? This is of course for non-crypto usage.
