Thinking aboout getting a Unicycle for XC rides - Have not riden one yet
Is a 26 a good start ?
If you do not already ride unicycles a 26" might be a bit of a challenge to learn on, however it would be a fine uni for off road or trail riding once you do learn to ride.
XC is a very very broad term.
Much of what you see Kris Holm riding, is considered XC by some. But then for others XC is anything that isn’t paved.
So telling us more the the kind of terrain you are on, what your goals are, and what you expect out of the unicycle would help people.
No matter what you say, people will tell you to get a whole bunch of different unicycles, but the more info you provide us, the better quality answers you can get.
26" or 24" generally. Many of the 24" mountain unicycles you will see are equipped with very fat tires, like 3", that make the diameter pretty close to 26" anyway. These unicycles are a little harder to learn on, but if you don’t have access to a “basic” unicycle for learning to ride, don’t worry about it too much.