With the walk-in front closet design of the new DRV Mobile Suites, the front of the cap extends farther ahead of the kingpin than it did on our 2004 MS 36RE3. In addition, the 102" width also eats into cab-to-5th wheel clearance when turning. The long bed dually doesn't have any clearance problems and can use a standard B&W Companion 5th wheel hitch - no slider required.
We've always used long bed duallies to tow our 5th wheels. That gives us room for a tool box ahead of the hitch and two (2) Yamaha EF2000is generators between the hitch and tailgate.
Rusty