As a sort of quick experiment, I slapped together a regex scraping of a single user's accounts page on SE.com and have put it up on the test deployment of se-flairse-flair:
http://test.se-flair.appspot.com/SEaccounts/[assoc-id]/
The return is, at the moment, a JSON object with the display name, the gravatar URL, and an array of sites, where each site has the various statistics displayed on that page. The raw HTML of the user's SE.com accounts page may be cached for up to 8 hours.
Please do not develop against this without talking to me first—the format of the data is subject to change and the service should not be considered at all reliable. Neither the JSON output at this URL nor the underlying scraping are used in se-flair (yet). If/when there's a more stable version with a more fixed output format, it'll be part of a regular (default) deployment of se-flair (at http://se-flair.appspot.com/
).
Please do comment with feedback.
edit 2011-09-22: Mostly due to repeated breakage of how I'd been getting Area 51 info, I've converted se-flair to using this scraping of the SE.com profile accounts page. This means that
http://se-flair.appspot.com/SEaccounts/[assoc-id]/
will now get the JSON data and that I consider it fairly reliable. I would strongly suggest not developing against it without talking to me first as the format of the data is still subject to change.