You're going to be maxed in payload with most crewcab 1/2 T trucks. Sure some of the reg cab HD 1/2T have high payloads these days but add in luxuries and the big cab and payload gets used up quickly. I think the only crewcab 1/2 T that has enough payload for you is the new alum F150 with HD payload package or possibly the previous gen F150 with HD payload package. That is different than just the towing package and cant be added after it is built.
That being said we LOVED our '10 Tundra Crewmax 5.7 TRD. Towed my 6600# loaded SP295 effortlessly even up 6-7% grades. I could easily pass semi's without any thought. I know plenty who pull a lot more weight than that with the Tundra. Are they over weight? Probably. It is up to the owner to decide what is safe. I would highly recommend Load Range E tires and maybe something like Timbrens or air bags to shore up the rear. The tires will take the squirm out and the suspension helpers will take the bounce out. Neither increase payload but they do increase towing comfort and I would say safety as well. I had Timbrens on my Tundra and would recommend them. They're simple and work!
For us we had to get rid of the Tundra due to space. My family a 100# and 80# dog and all our gear had us cramped and over payload. No chance of that happening with the new TV!
'15 XLR 27HFS
'15 Nissan NVP 3500 SL
Campers - Me, DW, 3 - DS (7, 5, 3), 2 large dogs