Welcome to MobileRead, madbuddha7!
You've pretty well covered the majority of the answers you might get. I'd add that Fictionwise.com's "multi-format" downloads are in the process of being reworked to include LRF format.
Also, pretty much any place that sells Microsoft Reader (.LIT) format is an option if you don't mind using ConvertLit on the files, followed by one of the apps that will make LRF files from a LIT file.
