Not sure how well known this is in the states, but Jools Holland has pulled a Grey Whistle Test reinvention over the last 15+ years in the UK with a 'live' music show broadcast (though not really live, yet) on Friday nights. [update: "Later" was on BBC America, maybe still is, we don't have a tv] The roll-call of performers is jaw dropping, though the dvd release earlier this year does veer towards better known names and leaves a lot on the editing floor... hard not too i guess. There is grumbling recently that the show is getting a little stodgy as it recently passed its 200th show. Anyway, daywrecker link here to over 3,000 session clips on youtube.
Trying to find the first episode ever...let's see how long it takes OMIL to rip it from his personal collection, because he no doubt recorded it (on VHS no less). I think Bjork was one of the guests (singing Human Behaviour maybe??). Clip above is Sonic Youth from one of the first shows.