Tho't this might be of interest to you. I just finished reviewing the Native Instruments Guitar Rig. It does both effects & looping. It's also a USB interface to your computer.
There are some audio files, including one that shows one way to make real music with real-time loops. (Actually, it's really just a socially accepted way to play with yourself.)
Warning: electric guitar content. Not for the acoustically squeamish.