I found the colors I want at fabric.com and I like the white-on-white ones they have. It's only 6.98 per yard for 108" wide (says compared to $9.99 at other places). I have quilts that have bright white in them and I couldn't find anything else that wasn't a natural or off-white. I have to measure 1 of the quilts again. It's very large and I am not totally sure that 108" is big enough with 4" extra around each side.
Thanks for the suggestions. :)