As the saying goes ........... your quilt, your house, your rules!
Of course, you can do it.
You said you do have smaller quilts you would like to use, so try it with another larger quilt or bedspread you have and see what you think.
I do it all the time .... flip a bedspread size quilt over to give the plain back.
Then lay my smaller quilt overtop.
I first did this with a large lap Christmas quilt.
Laying over a chair in the family room, did not do it justice. Nor did I truly get to enjoy it!
It fit the top of my double bed.
Just so happened that I had another quilt where the backing coordinated with it.
So the flip over happened.
And no ... it does not have to be white.
The one above is a black and gold backing. Perfectly suited the Christmas front.
I have a light green backed quilt that works well another.