Why is a hybrid/"flat-bar road bike" not capable on rail trails? Something like a Specialized Sirrus IS a cyclocross bike with a flat handlebar and better brakes. Plus, you get a wider range of gearing for all situations, rather than the very narrow range on most CX bikes. Unless you really want drop handlebars, you'll get more bang for your buck with a Sirrus instead of a Tricross, and it is probably even more trail capable (wider bars + better brakes = more control).
As for the X-Bow, it should be a 2x10 setup with SRAM Apex. If you see a 2x9, it is an older model with Tiagra. The price dropped for 2012, and the parts spec got better... so unless you are getting a killer deal on the 2011, I'd pass in favor of the newer one. 2x10 should not be an issue, most road bikes come set up as 2x10, no problems. The issue is that the XBow is 2x10 cyclocross gearing... in this case, probably 36/46 for the teeth on the front. Typically a road bike would either have 53/39 or 50/34. You don't need a wide gear range for CX racing, so race bikes get spec'ed with a very focused gear range. For general road riding, you usually do need lots of gear choices, so the CX gearing could at times be a hinderance. I think the Tricross comes as a triple, so no issues there, it's a wide range (it's also no really made for racing), as do a few others. It's hard to find good triple-chainring road parts these days, so don't discount a double (especially a compact double)... just try to avoid a CX race gearing, that would be limiting.