One feature you may wish to consider adding to vanity pool, the ability to specify case-insensitivity in bounties.

Whoever posted the bounties for 1Satoshi and 1satoshi paid for two different addresses differing only in the case of the first letter.  It's entirely possible that that person simply wants that name on firstbits, and would rather pay for one case-insensitive address.  Also, at the reward offered for those bounties, finding a case-insensitive match would be very close to profitable, but finding either of the case-sensitive variants is not.

Or maybe not in this case, looks like 1satoshi is taken on firstbits.