just like tiber septim did, hire some dragons to fight your enermy.
It would be something like give them a very high amount of septim (10000?) and they give you the word power to summon them.And if there is no enermy near by they will land and you are able to speak to them or command them to carry some item for you.
do you think it would be a good feature?
Instead of paying a large amount of gold why not have it that you must defeat the dragon(s) in combat, I only say this because the dragons in game don't really guard any large treasures. But your idea could work as well. But bare in mind that once you get so far into the game you gain the ability to call at least one dragon, 2 if you play your cards right with DG.
What exactly is a dragon going to spend money on?
They wouldn't spend it, if you go by lore dragons are greedy and love treasure. http://en.wikipedia.org/wiki/Smaug.
