I know this is far fetched and will not likely evolve, but hey, I'm bored and feel like posting. Oh and can't remember the feature I was meaning to suggest (I shoudl start doing that when I think of it instead of a week later) =/
This would basically give an object a parameter allowing it to store it's own money (keyed to the owner still of course), but give more contol over payment limitations and accounting functions. Tihs would be extended to llGiveMoney() in that it would except an object's key with given permissions.
K, so it's not neceessary and can be mimicked with scripting variables, but hey we can all dream.