Cross-Checks are widely said to run one size smaller than your normal measure and I found that to be true with mine. I'm 6-1 and would ride a 60 in most similar frames but the 58 fits me perfectly in the X-C. There's no real way of knowing, though, except to ride one, which is obviously a challenge with a bike that isn't stocked in a lot of shops.
I have the grey frame. It's discontinued and my sense is it's hard to find partly because lots of people don't like the new brown and want something other than black, like you. Not long ago someone was trying to flip a new grey X-C frame on our local Craigslist for like $75 over the regular price.