I think I've had a great idea but given the explosive nature of liquified gas wanted to run it by those who probably know a bit more than I do about the subject. So here goes.
On my project trailer I'm mounting a mini split AC unit on the tongue and it's really going to limit the space for propane tanks. I can squeeze in up to a 10Lb Worthington either horizontal or vertical but it will reduce the air flow to the AC unit which I'd like to avoid. I don't expect to use a huge amount of propane with just a small cooktop and Truma's combi on demand heater furnace unit, no regular furnace and no 3 way refrigerator.
I started looking at tank alternatives and began with the undermount on interstates and ended up looking at one made for Westies. It's an ASME tank 6" in diameter and 32" long with a serious bash guard. My idea is to mount it in my 6" tall frame so it doesn't hang down at all, not enclose it with belly pan, locate it near the axles for 100% protection and a straight shot access up into the coach to the cooktop and along the frame back up in to the water heater and add a remote fill kit just below the city water and shore power inlet.
It is expensive but would keep the tongue clear for the AC and reduce tongue weight.