I have a ricardo x carnival night mare and she has the best temperament you could wish for but she is 16.3 and very strong so it is an effort at times to hold her back when leading as she doesnt know her own strength.I broke her myself and she didnt put a foot wrong.Any one i know who has one say they are easy and laid back.He does get a lot of thoroughbred mares so that may not help any temperament issue.
The mare if you want to take a look is on the first page of my website: www.freewebs.com/ballyshanhorses/
I have a 7 year old Ricardo Z gelding out of a Ballinvella mare, and he's the most laid back horse you could come across, brilliant temperament. I have been told though that the bays have good temperaments and the chestnuts tend to have issues, but I suspect that's probably not true!
I love them!! Mark Kyle has one that he show jumps who is up for sale at the moment and he used to event another who was absolutely awesome!! He sold to the USA for unknown sums tho so not around anymore. This was him: http://www.queenholme.com/kurious.html
I have and 8yo bay RZ out of an Irish mare, got him as a 4yo and he has the best temprement - gentle if a little clumsy, loves attention and really enjoys his work as a dressage pony, although he never says no on the cross country course or SJ arena. He is 17'3 but never had a real problem with strength. He always asks to go faster although sometimes tries to sneek into canter in the hope that I won't notice!
He reminds me of a yellow lab - everyone is there to see him and give him treats.