"Towing" and "4.8 Tahoe" are mutually exclusive, do't even think about it.
We had an Envoy to tow our hybrid TT but knew it was max'd out. The supercab F-150 we have now does the job just fine since it's just my wife & I. The Ecoboost is overkill for the TT we now have but it tows sooooo nice.
SUV's have soft suspensions for soccer moms and you'll probably run out of payload, but you can overload a 1/2-ton pickup pretty easily also.
For GM's & Fords I'd be looking at models with the 6-speed transmissions. I personally don't like a Dodge but they have their fans too.