I'm also going with the group in saying check out different gaited breeds. Each does vary a bit in "butt" feel and disposition.
The TWH I owned when I was younger could canter like a dream and at a gallop could outrun all of our other horses (QH, Appy, Morgans, and Arabs.
Not the sharpest turner, but he won many fun events with me aboard.
In a former life I also rode a lot of warmbloods, European breeds, and several gaited breeds. When it came time to get a horse again, after being horseless for a while, I knew I wanted another gaited horse. Was looking at Pasos, MFT, SSH, and RMH.
As mentioned above, the Rockies, KYs and Mt. Pleasure horses have terrific personalities!
Mine is about as quirky, goofy, and lovable as they come.