As I mentioned in the other thread on permanency, one of our GMs had an interesting interpretation. (The first used Scion's suggestion of making it like an item, able to be suppressed for 1d4 rounds.)
She ruled that, sure, you can use dispel magic to take away a permanent spell. And at that point, the xp spent to power that permanent spell reverts immediately and instantly to its caster. She was going with the rationale that the xp spent to maintain a spell perpetually upon you is like a little packet of personal power earmarked for that task, and if the spell isn't being maintained any longer, that power you'd set aside for the spell goes right back to you.
In play, this meant that it made sense to dispel magic on people with permanent magical effects, because it got rid of the spell, period. But at the same time, people were actually willing to have permanent magical effects on them, because if they were dispelled, they just needed a day of downtime to put the spells back on and they weren't kicking themselves for wasting thousands of xp.
--
and lo, everyone was happy
ryan