Do you have any ideas on something different I could try when pairing meatloaf with mashed potatoes?

Yes, here are two fun meatloaf and mashed potato suggestions and one far out no meat meatloaf patty.

No Buns About It Idaho® Burger Loaf

Meatloaf Cupcakes with Idaho® Potato “Frosting” & Wild Mushroom Sauce

And how about making a Meatless Monday Meatloaf patty like this interesting one using Idaho potatoes:

Potato Burger