Not really what you asked for but the new Roadlink from Togo
is an interesting device. It gives you unlimited (subject only to network congestion) AT&T service
and WiFi rebroadcast. The AT&T service is only $30 a month paid annually. It has a dome you mount on the roof and you just feed it with 12v. Everything else is inside the dome. The dome is from Winegard, what’s special is the data plan deal.
This is a subsidiary of Thor industries who owns Airstream. This program was a result of the work Airstream did for the new Airstream Connect option. This is a whole lot cheaper at $399 and a self install over the Airstream branded option.
It’s not some super fancy modem or router in the dome but I suspect it will get the job done.