I'm glad you're as concerned about interoperability and backwards-compatibility as I am. Perhaps it would be helpful somewhere along the line to put together a guide of how to interface with Bitzi, including how to best store bitprints internally (raw binary, not baseXX strings), what URLs will perform which functions (www.bitzi.com/lookup/XXXX provides human-readable data), and other suggestions for maintaining compatibility in the future.

As far as data access is concerned, any standardized format would be fine with me. I have a strong preference for formats with Perl parsers already written, but that includes just about everything. XML would be fine, even the format that the bitcollider uses now would be fine. But it would be nice if this was decided soon, so tickets could contain useful information...

I'll share more about my project when I get farther along on it, but for now I'll just say that it looks a lot like Bitzi, but with FTP support.