Do Extended Cabs Come in Long Bed?? Looking for 5er Truck

Redwoodguy wrote:
I'm going to be buying a 34' 5th wheel.I've towed TT's with Suburbans, but never a 5er.

So, I begin looking for a used diesel truck, and I see almost exclusively King Cab, or Crew Cab trucks that look like short beds. I see all the advice for towing 5ers says, "Only use long bed."

Do these Crew Cabs come with Long Beds? I sure haven't seen any in the used truck listings.

Any advice appreciated.