I believe its because everybody loves me, but I had a hell of a time stealing 500 gold in whiterun (had to open the master lock display case in dragonsreach). Is there any way to make it so that people don't like me as much, and thus are unwilling to part with their goods? Amren's house in particular didn't have a single stealable item in it, and I did his sword retrieval quest.

Steal the unique gems. They count for your goal. One in dragons reach, another in Jorrvaskr. This is what I do with the Bedlam jobs. (I am not much into stealing. I prefer Vex's shill jobs.)

Take a sweep job and a bedlam job in the same city (you can cancel jobs until they line up).

Potions, my friend - some of them are quite expensive, and all expensive potions are still flagged as 'stealing' even after befriending everyone in the city. And they do respawn. Edit: Same for ingredients.

Thanks for the help, just needed to get enough jobs in Windhelm to have Summerset Shadows available. Why is it that the thieves guild has so much more time invested in it's completion? I just recently finished the Stones of Barenziah quest, nearly a year after the game came out.

I cleaned out the blacksmith in whiterun. got enough items to match 500 gold.