All cotton bats that I have seen/touched are low loft and quilt up pretty flat. You still get definition of your quilting designs but fluffy is definitely not an adjective I would use to describe cotton batting. Cotton gives the old fasioned "flat" look to quilts and will usually give a nice wrinkle to the quilting stitches after washing. Quilter's dream does make a Supreme loft and a Deluxe loft cotton. They claim it to be a higher loft but I have never used it nor even seen a sample of it.
http://www.quiltersdreambatting.com/user-guide.htm
If you want fluffy go with a higher loft poly like poly down, Fat Batt, Quilters Dream Puff or Quilters dream Deluxe loft poly. Wool is also very fluffy but also very spendy.