Geeez c'mon, what did the big bad mean keyboard ever do to you?
Heh, seriously though, breaking it's functionality wasn't necessary... My Logitech F310 has keymapping within it's own software/driver suite.
There is more than one way to skin a cat as they say.
Bottom line, your keyboard in PSOBB is now completely borked you say? You've tried trying to find any and all PSOBB .ini files, anything related to the keyboard binds?
Alright... Well as far as I can guess, there is one last place you probably haven't tried on your hard drive but this one will be the most difficult and tricky to try to rectify.
Your Windows Registry file. My educated guess is to try to find any and all Sega/PSOBB/Phantasy Star Online Blue Burst registry entry references and delete them completely out of the registry, (REGEDIT.EXE) hopefully one of them is tied to your forced keyboard binds. Then try to completely reinstall the game with the original Ultima PSOBB installer .exe file.
Again, this is quite risky, one wrong registry entry deletion can possibly seriously screw up your Windows install or another installed program. However, you've exhausted all other avenues of solving your problem, this is a last-ditch solution so tread carefully Foxen.
Hope this helps, good luck, you're gonna need it.