I don't know if anyone else has experienced this, but I can't seem to get any more bounty quests from the innkeeper or the steward in Whiterun. I know that they are supposed to take a while to respawn, but shouldn't they be repeatable? By the way, I've waited 30 in-game days outside of Whiterun hold and still there are none available.
Spoiler Could this have anything to do with the stormcloaks taking over Whiterun and Proventius Avenicci being replaced by Brill as steward? The other holds (with exception of Haafingar) seem to still give out bounty quests even though they were liberated by the stormcloaks.