Well, a bit of research this evening shows that other companies and OSS working groups have beaten me to the product, but I'm happy to have come up with the concept on my own.
I've been poking at objects and data structures the past few days, and finally realized something. I'd designed a decently usable XML-tree object, but couldn't figure out how to easily browse and alter the tree. A few minutes ago, it occurred to me - I need three storage classes if I want to parse an RSS feed into manipulable objects: header-stuff, feed info, and items, each with its own optional iTunes tokens. I'll be working out the details tonight after a meeting I'm attending.
I hope this bit of chatter gets others interested in working with me on this project, since I'm going to need some help building the GUI.