What happens when a vehicle you want to trade-in is worth more than the new vehicle you want to order? would you walk away with a new truck and cash? or do dealers not want to trade like that?
I would think you'd take a bath on your trade, but a quick check on kbb.com says that the trade in book on the Laramie version of your truck is worth close to $52K. If you did trade your truck in and the dealer were to value it that high I would imagine you'd get a 2016 Colorado and a check for however much you could negotiate. I'm not sure about your state, but in Washington you only pay sales tax on the difference, so you'd be buying the Colorado with no sales tax.