TWH's are probably the most common but you'll see about any laterally gaited horse at a field trial. Occasionally someone will show up with a diagonal gaited horse like a QH but not often, not because there is anything wrong with those horses in terms of the physical and mental qualities needed, they just wear the riders out at the pace the lateral gaited horses can maintain. I've seen the occasional QH/paint that will move out darn good in a 4 beat flat walk - my neighbor has one that I can hear him coming and swear it's a TWH but he shows up on this fancy paint with its ears forward, head out and gettin' on down the road pretty fancy - it'd be a good one and I think is for sale.
I'm looking at a new foxtrotter this weekend - they've gotta go get him "off the mountain first".
