Our TT has a factory installed one-piece shower made by Shower Enclosures of America (SEA). It's around 30x48". They don't seem to have a website you can look at and may need to contact them on where to buy.
I think a residential one might be an issue due to the height of the base. Residential bases aren't very tall and no access is needed underneath. An RV type is raised so you can get at the P-trap & drain. But in a TH you might have more height available and could just build a raised base/plinth. Some residential showers need to have a base of mortar (or sometimes spray foam) to prevent the floor from flexing and cracking. Some have thick reinforced fiberglass floors that don't need the additional support.
You'll want to have access to the P-trap and maybe the valves. Our shower has a round access hatch like in the photo in the base and next to the valves. These can be purchased separately.
One other thing I can think of is that our SAE shower has a latch that locks the sliding doors in place for travelling. You'll want something that securely holds a sliding or swinging door in place.
