Just thought I'd mention this cool website, to any other jazz-funk/fusion fans,
http://www.darkfunk.com/latest_shows/ - some very cool live fusion concerts available for download - none of this stuff is commercially available. The available material changes regularly: right now I'm listening to Herbie Hancock's Headhunters (Kansas 16/1/1974) - very cool! (no longer available on the site though). Last night I got a complete concert by Miles Davis' 1975 band (scorching!).
Sound quality of these recordings is variable - they are bootleg audience recordings, but are worth checking out if you're a big fusion fan (like me!)