There is a "Record" window, i have not tried it, but it would be a cool option to add a "single frame" capture button for StopMotion animations.

http://developer.skolelinux.no/info/studentgrupper/2005-hig-stopmotion/

Stopmotion is a Qt program that is a frontend to ffmpeg and dvgrab as is Kdenlive for capture. It might be nice to integrate it, but not necessarily.