I don't know of any specific adjustable TV mount, but there was a recent recall on mounts that "articulate" ...seems they were failing at the joints and dropping the TV when installed in stix and brix homes. That can only be more of a risk in an RV, given the dynamic stresses.
Given the potential for catastrophic failure, I would consider installing additional safety restraints to limit the risk. Small cables, long enough to accommodate the full reach of the articulation, attached to the back of the TV and anchored in a structural member would be a good approach.
Check the Consumer Product Safety website for detailed information on the recalled TV mounts and proceed with caution. You should not install any heavy device over the pilot seat, regardless.
Hope you can find something that works safely and effectively for you.
Jim and Fran in Central Florida
1989 Country Coach Sedona Mark V
Turbocharged Detroit Diesel 8.2L "Fuel Pincher"