I know this is a late posting, thought I would add some important info.
Not everyone wants a bigger and bigger 5th wheel, depending on what type of RVing you do a smaller 5th wheel can be ideal, I personally pull a little 24ft 5th wheel that serves me very well for camping in many state and federal campgrounds, as well as a lot of boon docking. I have both a short bed and long bed Silverado, and can tell you there is a big difference in maneuverability between the two, both are ext cabs.
The shorter you can keep your truck, the much more maneuverable your setup will be, this is really important if you do a lot of primitive boondocking. The beauty of smaller 5th wheels is you can get them into some amazing spots you would not think you can. A slider hitch on a short bed is a must if you do any backwoods camping.
If you are just hopping from RV park to RV park, then it really doesn't matter at all, get what you like. I do enjoy the extra cargo space of the 8ft bed, but I can't park it in my garage. As far as street parking, SRW longbed truck is not that much more difficult to park than shortbed.
