The last paragraph summed up all my questions perfectly.
Right now, a Crew Cab 4x4 Colorado WT optioned how I'd like it has an MSRP of $35,215. I think that price tag leaves room for them to want an extra $2k (not that I'd want them to) for a diesel.
I just hope they don't pull a Cruze Diesel with this thing and make it available in the top trim only, and for a pretty penny more to boot.