HOLY SHIT, that's a good fucking question. I thought Fripp changed his mind before they actually had him in the studio? That's what he wrote in the Young Person's Guide booklet anyway, that they cancelled the studio session for Elton to sing on the Poseidon tracks because Fripp didn't like his debut album. Maybe there's actually been a tape of Elton singing "Pictures of a City", or some shit like that, hidden away in a dusty cupboard for all these years. How wild would that be?? Bryan Ferry was apparently also on the list of lead singers they auditioned...