Stan,
There will be several things that will require major changes to replace your Splendide with a stacked unit. First, there will be extensive rewiring to get 240 volt service to the residential dryer, and you will only be able to dry clothes when you are connected to a 50 amp shore power service with opposing legs (240 V) (not all 50 amp shore power boxes are 240 V) or the generator is running. Depending on the way your coach is wired, you may even need to replace the main A/C breaker box (not enough circuits). Next, you will have to make cabinet modifications to accommodate the extra unit, and give up that much storage area. Then you will have to cut another vent through the side of the coach for the new dryer.
The Splendide unit is a good washer and dryer for the purpose that it was built for, and if you take the time to learn the proper way to use it, it gives good results. You will probably find the change to be a big mistake.
Gerald