Do you mean to supply you gas, or the system used?
12-15 years ago we purchased a Coleman, Hot water on demand, still have it. At the time it served us, we had the room to carry it.
Now that it's just the two of us(mostly Swagging it now, if we don't take the hard floor rear fold camper), we use a collapsible bucket, boil some water, 12 volt pump shower run off the second battery, which is great for us atm.
I guess it depends on your needs.
You don't use magic to disappear, ya use a 4x4 & Swag.