Here's a link to an interesting chord progression that departs from the standard I-IV-V. It's even more interesting with a VIm bridge, which I haven't recorded yet. If anyone's interested in developing it, let me know. It's borrowed from "Love is the Saddest Feeling" by Savoy Brown, which is actually more Rock than Blues, so one could do a lot with it. I feel the II-IV significantly heightens tension.
SoundClick artist: River Bottom Blues Band - page with MP3 music downloads