What specifically is your objection to a second full-size fridge? Weight, space, anything specific?
If the main thing she wants is just more space, go with a basic freezer on top model. It doesn't have to be HUGE to work. If she wants a side by side or French door or freezer on bottom, she probably has a reason. Unless you have some compelling reason NOT to get what she wants, then get what she wants!
I would avoid an icemaker. They are responsible for 50% of all repairs to new refrigerators. And unless you have sediment filters on your water system, you may pick up some grit that can cause it to malfunction. Worst case scenario is a flooded RV.