I just discovered this - the internet archive has a live recordings archive.
Whats VERY interesting, is the HI DEF recordings... use the search tool for "flac 24 bit" and you will find 24bit, up to 192khz recordings... some AMAZING stuff..
These can be burned to a DVD-A and played on some DVD players.. Its like being at the concert... great great stuff!!
One of my current fav's - a little modern Jazz Fusion:
Garaj Mahal - Live a Keene State Solarfest
Its eclectic, but the sound is unbelieveable!