I mentioned in the Add-on Compatibility Reporter post, I had installed Firefox 7 Nightly but was having trouble getting the addon comparability ‘safe-guard’ turned off via an about:config tweak as I had in the past for other developmental builds. Girish Mony commented for those who just want to disable the compatibility checking add the following Boolean entry and set it to false:

extensions.checkCompatibility.nightly

This only works for Firefox 7 Nightly builds. Not sure what is going to happen when Firefox 7 moves to the Aurora channel on July 5th.