Technically, there is no such thing as a B+. Winnebago came up with the A,B,C classifications years ago based on how the MH is constructed.
A. Built from the ground up using a truck chassis.
B. A converted/gutted/extended van, can have extended roof.
C. Starting with the cab of a van or truck, perhaps the chassis, build the living quarters. Many C's have a "Cab over" bed but this is not a requirement. All B+'s are in reality Class C's.
An example is The old Winnebago Rialta which was based on a VW van front end (and only the front end) delivered to Winnebago who added the living area. Look at Winnebago's website and you will see the Aspect which is a class c but is similar to what others sell as a B+.
Marketers came up with the B+ to differentiate the style from the cab over bed look but it is still a C.
The C+ term I suspect refers to what some call a Super C which is a class c MH based on a big diesel truck cab and chassis, with the living area added on just like any other class c.
Tom Wilds
Blythewood, SC
2016 Newmar Baystar Sport 3004
2015 Jeep Wrangler 2dr HT