Large unquilted areas

I am presently designing a quilt and have a problem,
and since my mother has passed away recently, I need to
ask someone else for help.

The quilt will have two areas that would look best if
they had no visible quilting. I know that large areas without
quilting will have tearing and bunching of the batting. The
two areas would be 1.5 ft. x 1.5 ft., much larger than is
usually acceptable.

The solution I have come up with is to add a very -thin-
fabric on top of the backing and batting in those areas and
quilting those areas with a simple grid-work to stabilize the
batting. Then I will add the top and quilt those areas that
will have visible quilting.

My question is will this work, or is there a better way
to leave large un-quilted areas?

Thanks in advance.

Shorti