In reply to OP
I have rubbish temperature regulation so this may not apply to you.....
I don't think clothing exists that is cool enough to do hideously strenuous difficult exercise in the possibly sunkissed heat of the day..... but also allows you to float about happily in cold conductive water that could easily be 10 to 15 degrees colder.
I just don't think it's possible. You could get something that'd keep you warm in the water but climbing in it would suck. Unless the route was really easy (For you) in which case you could just have ditched the wetsuit anyway and played the numbers.
Might be better to put the effort in ensuring that you can get out of the water quickly instead. Though that won't help with the cold water shock of course. But then neither would a rash vest either.
IMHO