I've recently returned to BBEdit as my primary development editor after spending the past few years with the increasingly neglected TextMate. One thing that I missed from TextMate was some nice 'PyFlakes' integration. Since adding PyFlakes to my daily workflow in TextMate, either through the 'PyCheckMate' option or via the 'PyFlakes On Save' option (which popped up in a tooltip), my module imports have been cleaner and refactorings have gone more smoothly as I can catch forgotten names and imports in moved code.
The first thing I did when I moved to BBEdit was to rig up a quick script that ran PyFlakes and bound it to command-shift-V (V for Verify, or validate), based on the PyFlakes-On-Save TextMate command (which I found in a Zope bundle, I think). My script just dumped the results into a new BBEdit 'Unix Script Output' text document window. It worked, but was not particularly helpful. BBEdit has a 'check syntax' command built in that will catch SyntaxErrors in a python file, and its results go into the 'search results' window which allows you to step through the errors nicely in a dedicated window. I remember using something like this with Emacs and things that modified Make-mode to jump to error results in unit tests, making it easy to step through failures with a single key-chord.
Well today, I finally found how to get my results into that window. The script is now up on GitHub in Gist 1157742.