Looking to diy a quilt case, please

Sorry, but you maybe on the wrong site. If you are looking to buy something!.

I have a lot of quilts but my daughter and granddaughters has their names on them

By quilt base do you mean a bottom? After all a quilt is just two pieces of material with batting(cotton sheeting) between. Where is it written you can't use a second top as a bottom? OR simply buy a sheet of same size you want quilt and use that. Check out allfreesewing.com Enter quilts at top in search bar.

We're here to help, but you have to help us by being more specific: by "case", do you mean a case to hold and or display your quilts, or do you want to, for some reason, torn a quikt into a case, ie like a duvet?