Willie Carson - because I think he's hilarious when he commentates
Frankie Dettori - because it would just be fun
Princess Anne - to see if the Royals do know how to dance and a royal jive would be soooo entertaining
Clare Balding - because she seems game enough for anything
Carl Hester - to see if he can dance as well as his horses!
Lyn Russell - to see if she can actually, possibly, maybe just for once pull a face that isn't some form of a scowl (every time I've watched her in showing class she's always scowling at something) although it might make a good paso face!
A P!! because he is well known and seems to be up for most things! or stick an equestrian in I'm a celebrity.. reckon most of them would nail it (can you imagine Olly Townend as an eg) - screaming at insects? no chance, rats? we're used to them, drinking/eating odd things.. well judging by the state of most peoples hands by the time they get to that cup of tea or coffee we aren't a fussy lot...