I can fit my Raptor 700 in the back on my Ranger but not much else. A full size will fit a lot more but sometimes at the expense of gas, depending on how you drive of course. I have no need for a full size so that is out of the question.
As far as the crew cab Tacoma(short bed) goes my buddy fits his Yamaha 450 in the back with the tailgate down and a bed extender. I will be getting the same truck at the end of the year but I will be towing my quad around on a small trailer like this:
that way I can just put camping stuff in the bed. It all really depends on what quad you own or will own.