OK, for a dream lineup that probably wouldn't really work:
Vocals: the young Ronnie Dio (circa 1977)
Guitar: Michael Schenker
Keyboards/Guitar: Ken Hensley
Bass: John Entwistle
Drums: Ian Paice
Here's one I'd really like to hear - Clutch plus guests. For bluesy, stonerish jam rock I think this lot might actually work:
Vocals: John Garcia
Lead Guitar: Warren Haynes
Guitar: Tim Sult
Bass: Dan Maines
Drums: Jean-Paul Gaster
Vocals, lyrics and inspiration: Neil Fallon