Spendide Ariston Stackable. The dryer is a model TVM63X and the washer is a model ARWXF129W. Yes this is in a Columbus. Tight fit to say the least.
Another option is non stackable all in one unit. Splendide makes this style also. Less expensive, less cramped, but supposedly takes longer to do laundry with the all in one unit. But if you have laundry machines in your RV, you are probably retired and have all the time in the world compared to us working stiffs.
Pic of a Spendide 2000S - no idea if this fits in the Columbus models. Pic is just a reference of a non stacked all in one unit.