The way I see it, a dream supergroup would include performers who you'd wanna hear playing with someone else, because of... / whatever your reason is/...
Aretha - probably the best female singer ever lived - sang her best performances with large concert bands, and not in her regular concerts or even on studio recordings. So, I'd love to hear her singing with a monster band and some great supporting cast.
My
Soul Supergroup would be:
- Aretha, Marvin Gaye, Temptations - vocals
- George Duke, Stevie Wonder - keyboards
- Marcus Miller - bass
- Tony Allen and Billy Cobham - drums & percussion
- Chicago - brass section
- Prince and Leo Nocentelli - guitars
Rock:
- Robert Plant, Freddie Mercury, Mark Knopfler, Guillan - vocals
- Knopfler, May, Page, Gilmour - guitars
- Marcus Miller - bass
- Banks, Wright - keyboards
- Kenny Aronoff and Ian Paice- drums
Mind you, today's level of concert and studio musicians is so incredibly high - most of the current big stage bands can back almost anyone and the outcome would be a super-amazing performance. Just look at SNL band, or former Letterman/Schaeffer band or Roots - they can play anything, literally anything, and it would sound tops. I highly recommend watching a concert of Eric Clapton's with Wynton Marsalis Band - that's a supergroup right there... Endless topic, of course...