Thank you everyone. I appreciate all the inputs. I'll likely go look at the megacab, but I did understand the extra room was behind the seats (plus I wouldn't get an 8' bed). As I indicated in my original post not interested in a class A (or C) and getting a 1 ton van or old suburban/expedition doesn't get me the increase in towing I'm looking for, plus no 5th wheel.
As someone commented, it will ultimately come down to where and how I will compromise. I have some time as I'm likely at least a year out...just starting the planning.
Thank you again.