Although it would be nice to see, I think you're pretty safe. I don't see the regular Teryx getting a bigger motor any time in the near (or distant) future. They call the KRX a "teryx" too, so that is your 1000cc option. I don't see them putting the money and time into the engineering and production of a bigger motor for the standard Teryx models. But I would assume that a KRX 4 seater may be an option that hits the market in the next year or two.
Honestly after having driven both the KRX 1000 and the regular Teryx 800 I don't think it needs the bigger motor. I wouldn't really want to go much faster in this body style anyways. Get the KRX1000 if that is your style. I may buy one too for different purposes.
I was thinking this as well, that it might get the 1000 cc motor, but I wasn’t going to wait and reading a bunch of articles, reviews, and seeing your guys responses on this forum. I choose to get one this year. I’ve only had it for a week but so far I think it has plenty of power for what I want to do. Just wish the governor was shut off at 60 not 50.