There should be no problem with this fabric combination because cotton and linen are both natural fibers and would act very similarly in combination. Both take dye very well and evenly. Linen also wears very well when used in clothing, therefore, it would wear well in a quilt. I think it would offer an interesting texture and hand. I want to see it, I have not encountered it so far. I do not like to work with fabrics that are cotton combined with a synthetic such as polyester, nylon or rayon.