I'm not sure how to mod the board, i haven't looked into it yet but was thinking bout it too.
I'm pretty sure i saw something about modding the chip itself somehow and then the bios would go up to 1.85V, if you find out anything about this let me know.
On my old Xp1800 pally the bios would goto 1.85V also, it really sucks cause my tbred will definately go higher with more voltage.