ramblinChet,
I bought a single LG NEON 360 watt panel from CED Greentech in Ventura, CA (they have many other locations - click on the contact location tab top right of the web page)).
https://www.cedgreentech.com/
I called and told them I wanted a single residential size panel between 350 and 400 Watts for a camper. They gave me several options with the LG panel being the most expensive but is higher rated for quality and has lower degradation rate than the Q-cell panel. Available panels will vary by warehouse location. The Panasonic panel had less power than I wanted. These panels all have the 40" - 41" wide x 67" long configuration.
Here are the choices I was offered:
QCELL Q.PEAKDUOMLBLKG9+380 380W DUO BOB MODULE $220.12
LG LG360N1C-N5.AUS 360W BOW MONO MODULE $309.88
PANISONIC VBHN330SA17 330W MONO BLK/WHT $281.71
380 watt to 405+ watt panels are available in the 41" wide by 80" long configuration.
Raven, Hawk, Grandby and Keystone roofs are 80" wide. The other FWC campers are only 75" wide.
Panels up to 450 watts are available in the 41" wide by 83" long configuration. (these dimensions vary by manufacturer). These panels are wider than the camper roof and would probably need to be mounted along the length of the roof but roof vents might be an issue due to the width of these larger panels.
I am sure there are other Solar Panel distributors out there. If none close by try calling installers to see if they will sell you a panel. Maybe they can add a panel to one of their orders for larger quanty.
Shipping cost of a panel would drive the cost of a single panel too high I think.
For reference I did a comparison of multiple single panels vs a single large panel vs weight. A single large panel is the way to go.
Here is a link to the spreadsheet I posted:
https://www.wanderthewest.com/forum/topic/21016-what-are-the-measurements-of-the-roof-vent-locations-on-your-camper/#entry245183
Good luck.