Generally, RVs plumbed to install a w/d will have room for 1) combo w/d or 2) stackable w/d. RV units will be about 24" wide for the main fit concern--look for those models, and be sure the dryer unit (if stackable) is a 120volt unit, not a 240volt unit. Splendide is a brand intstalled a lot in new RVs--and have both combo and stackable units. Whirlpool is also used a lot in the stackable models. I have said 'stackable' because a lot of RVs don't have room for side x side units, and a lot of RVs only have room for a combo setup.
Go to an RV dealer and see what models are installed on the display units and get the model #s to research. Or go to campingworld.com and see what they have online to get some ideas. And you will also have to consider whether you want the dryer vented outside, or a ventless dryer (I don't recommend these).
And, of course, measure your laundry space FIRST before buying anything.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired