I made this quilt. The white is bleached muslin from JoAnn's. It's been appraised by a certified quilt appraiser at $1500. Why shouldn't you use muslin? No reason I can think of!
(It's an Ann Orr design from the 1930s called "Postage Stamp Rose". It's 6205, 1 - inch squares, hand quilted 1/4 - inch inside each square.)