I'm always a sucker for movies where a character has to go fix something/deal with something in the past to improve something in the present ("High Fidelity," "Broken Flowers," etc.)

Maybe something happened with these friendships that made the protagonist into the slacker he is.

And more than just fighting to save the house, maybe he's fighting to save himself.

I think there's a strong concept hiding somewhere behind that logline.

Uh, wouldn't be so keen on using Jim Jarmusch for structure. I love him and Bill Murray (didn't care much for Broken Flowers,) but it was typical Jarmusch - meandering and episodic. Jarmusch is always interesting, but from a purely spec perspective, not a good example. He's Indie through-and-through.

Modern road movie classics like Sideways and Thelma and Louise are better examples of structure, though both use a buddy system to integrate the plot.

What could focus the idea is an antagonist. For example, what if the IOU's encompass not just childhood, but teen years, as well?

Say, the protag loaned money to an ex-friend who used the money to start a business? They had a falling out and haven't talked to each other since. When the protag goes about the IOU's, he discovers the antag is wealthy and the protag thinks he deserves part of his fortune?

Another idea is to show how the slacker has failed to live up to his potential - and each IOU feeds his arc - the IOU's each have something the protag lacks, whether it is material things, or a family, or a GF, or inner qualities, like compassion, bravery, etc. Then, it goes from merely being about financial gain to changing his life, as TUL suggested.

Or more to the point, it could use a second concept, as explained by Wordplayer:

http://www.wordplayer.com/columns/wp52.The.Second.Concept.html

In the end, however, it comes down to if the writer has passion for the project and if he connects to the material. In the end, it'll make for a better sample than a perfect high-concept idea he cares little about. Good luck.

I think that analysis was extremely helpful and useful. Thanks for that!