I do faux trapunto on my domestic machine and my Sweet Sixteen. It's just two layers of batting, either cotton bottom layer and wool top, bamboo bottom and wool top, or wool for both layers. The background is heavily quilted which results in interesting texture depending on how quilted and allows the less heavily quilted design elements to puff up. It is very easy to do, and the quilts I've done with wool are all very light and drape nicely.
Tim Lattimer has a nice Youtube video where he's doing a traditional form of trapunto by hand. For the quilt he's adding trapunto to he uses a wool yarn that he threads through an upholsterer's? needle and then inserts it through the top of the quilt into the area where he wants the trapunto effect. No cutting slits in fabric that then need to be hand sewn.
Rob
Rob