nativetexan

http://www.modabakeshop.com/2011/11/...y-playmat.html
here's a baby quilt done that way. i did one with cotton fabrics and batting. but i put my batting the full circle size and that made it a tiny bit difficult to fold over the edges and sew well.
denim can be heavy, if you aren't to sleep under it all will be fine. sew circles into rows and then into rows. good luck.

bearisgray

How about starting with a lap/crib size? and then, if you are having fun - you can make it grow into a king-size?

Feathers-N-Fur

Check out the video at this link. It uses the same technique, but with a template and layer cakes instead of denim. You would get that look, and quilt as you go, but lighter weight.

http://www.missouriquiltco.com/notio...-brandy-s.html