Did your niece see your daughter's? It sounds like she may be asking for the same kind and just doesn't know it is called a wholecloth. You could consider a monochromatic quilt. Any quilt pattern can be done in a monochromatic color scheme. Pick whites, creams, light beiges, white on cream prints, white on white prints. Just make sure you have enough change in the value to distinguish between different fabrics. But before you go to this effort I would ensure your neice understands she won't get a wholecloth like your daughter's.