Hmm. This is a problem, because I want to know how much to charge for a permanency spell to grant greater magic fang and other spells. As listed, with the current rules, if you had a 10th level sorcerer and a 20th level druid, to give a monk up to a +5 enhancement bonus to his attacks, it'd be 7,500gp for XP, plus 600gp for the greater magic fang spell, plus 500gp for the permancy spell. So 8,600gp for the equivalent of a 50,000gp +5 magic weapon. A bit cheap, isn't it?
I mostly wanted to start using permancy as a simple way to create magical traps, other strange magical effects, and even better, to allow odd magic bonuses, like enchanted tattoos and stuff.
Rather, if we charge 25gp per XP, we get a cost of 38,600gp. That seems like a fair trade for an item that you can't give to a buddy.
I'd rather lower the XP cost of spells you'd normally want to hire someone to cast for you, like commune.