Trial versions of software usually appear when the company are very confident in turning demos into purchases. That's why x2 demo doesn't exist. :)
Diva softsynth is a very good example of A company completely confident in their product. It is just so good that anyone who downloads a demo will probably end up buying it within a few hoirs. Sonar usually do le versions bundled with soundcards etc, but I don't think they are confident to do that yet with x2 for obvious reasons.
Download diva though, it is truly a game changer as they claim it to be. By far the best piece of musical software I have encountered in the last 10 years.