Still stuck on Purple. The track I referenced yesterday came from a DVD I just found; Deep Purple live in '72/73, and it turns out that little else of live video exists for this crazy-assed band. At least that's what they're saying, so when they release other DVDs, we've just got to get them.
I didn't listen to the whole thing yesterday, and it turns out that one of their three encores from the March 1, 1972 Denmark show was Lucille, from Little Richard.
Damn, it screams; got to love Roger Glover! Just found it on youtube: