"are 10mm glocks any good as a trailguns?"
It depends on which trail. Anywhere in the continental United States it's a good choice.
What are your options? .357 mag, .41 mag, .44 mag but weight and capacity make them less desireble than the m29. With that Glock you have 10 rounds in the gun and 15 rounds in a m20 magazine as a back-up. The ballistics tell a good tale with the 180 and 200 grain offerings. Total weight is less than a revolver and its size allows more carry options. There's really nothing not to like.