Just a few ideas...
Twist on break in and steal - break in and plant some kind of incriminating goods. Forged letters implicating the target in some kind of scandal, wiping clay into the treads on their boots (to make it seem like they were at the river last night), or just general contraband.
Twist on assassination - break in and kidnap. Or, break in to protect someone from another assassin, sent by a third party. Breaking in during a siege of a city to let in the army?
Lastly, counter-espionage is a good way for the PC's enemies to get their own back. Any of the suggested ideas can be used in reverse.
As a reference, Robin Hobb's series the Farseer Trilogy (Assassin's Apprentice, Royal Assassin, and Assassin's Quest) and the sequal series, the Tawny Man (Fool's Errand, the Golden Fool) have some of this sort of thing, but mainly sneaking around and spying than breaking in a stealing. They are also a pretty entertaining read.
Some of Feist's work has this sort of stuff as well, particularly the Acoma trilogy (Daughter of The Empire, Servant of the Empire, and Mistress of the Empire.) Full of political machinations, infiltration missions, etc. Lastly, Sailing to Sarantium by Guy Gavriel Kay has some political stuff, though that's probably the least useful.
Hope that gives you some ideas.