Ramsey, contact Justin, Jenna, or Julie over at Black Bear Performance. They are one of the premier tuning companies in the country when it comes to late model GM trucks. They use EFI Live, which is a very in-depth tuning software/diagnostic suite. Using their equipment, you can scan your truck via the OBDII port and create data logs, which you then return to them, and they take that data and custom tune a PCM to YOUR specific truck's needs, as well as your preferences for shift firmness, shift points, torque management reduction/elimination, etc. Off the shelf tuners are pre-programmed to edit a very specific set of parameters most of the time; a "cookie cutter" tune, if you will. A custom EFI-Live tune is a much better option. They can also tell you if you have any maintenance issues that need to be taken care of, recalibrate your speedo for different tire sizes, adjust active fuel management settings or turn it off completely, among other things.
I have been using them for a long time (first tune on my old Yukon was done back in 08, IIRC) - they are awesome, and have a large forum presence here. Jenna (JennaBear) and Julie (Julie@BBP) are on here regularly answering questions. PM them if you need more info.
ETA: No, I don't work for them. Just a happy customer.