Yes,,there are of course a German brand for RV-heating.
The main brand is "TRUMA", they make dpendable furnaces, but they require totally different "basics":
-10mm steel conected propane suply.
-total different thermostates (10 wires!)
-total different exhaust and airintake
-significant smaller diam. for airhoses and total different airoutlets
If you begin to change over to "german" appliances, it requires an enormous amount of cash to change them ALL (!), you can't just change "some", because of the dufferent pressure also (we use 50millibar, ni idea what that is in psi...)
The "power" of these TRUMA furnaces is very limited, the "very big" 4000e brings max. 3,3 kw (converted to BTU almost half if the NT30-SP.
Last but not least, a TRUMA 4000e cost 1450,00€ , without ANY hardware to install.
So, now you might understand, WHY i prefer to dtay with my SUBURBAN...!