We recently upgraded from a Chevy S10 xtra-cab. The small truck-xtra cabs really aren't comfortable or practical for passengers IMO.
We bought an 06 Chevy Silverado xtra-cab and it has a full back seat that can sit ~3 but 2 (or 1 & dog) comfortably.
We actually get better towing mileage on the big truck with a 4.8L V8. It also has a 6,800# tow rating and towing the TM is not an issue. We don't even use a WDH.......although, we did add air bags due to all the extra weight that we carry in the truck bed (camper shell, bed-slide, built-in cabinets and misc cargo).
However, if you really want a passenger carrier, you may want to look into a crew-cab. We wanted an 8' bed and the crew-cab has a ginourmously long wheel base that is difficult for towing IMHO. A crew-cab with a 6' bed may be tolerable. It's about the same WB as my 8' bed truck.