HOFMAN  This seems pretty unnecessary. Using the version string in the URL is not even the proper way to pass the version. The version should be set in the appcast, which is much more reliable and precise. It is not even guaranteed that Sparkle will support getting the version from the URL in the feature, my guess is that it won't.  
(Version 1.2)

ROMAHONY  Seems over the top for something that doesnt save much time. I created a script that checks out your source compiles it, checks if it compiled correctly, puts it in a dmg that can be used for sparkle and uploads it to your webserver, posts the build info to a db also. I have been using this for sparkle for months, with mine you can do nightly builds with cron or even have a commit hook for development.

http://www.ruairiomahony.com/portfolio  
(Version 1.1)