Look up the nearest upholstery/fabric shop to you.go there with your needs and talk to them.They usuall have people that do custom work.But it Ain't cheap.
Kathi

Andrea..maybe I can help. I can email some pics of what I've done in the bedding category.

If you sew, it's not hard to make your own duvet cover for a bed, or even a comforter.

I would expect that the sheets would be the worst part. You can always make a quilt any size you like.

Rosefolly