GM has shared the Colorado/Canyon platform with Isuzu and this is the result-

http://www.isuzu.co.jp/world/product/dmax/index.html

So I'd say the engineering is done for GM to introduce a diesel Colorado/Canyon. For someone like me commuting 100 miles a day, with light hobby farm chores on the weekend, it looks like a perfect solution.

I'll save the 2500HD for hauling the horse trailer.