One of my guild members showed us a quilt done this way at our last meeting. She is a very talented professional longarmer. If I understood the process - first she did an all-over on the pieced quilt, which was rectangles of neutral tones, then she laid down her applique pieces (fused to a very lightweight fusible) and stitched around them, then clipped the edges. Here's her blog showing the quilt and explaining the process - and I took the picture!
http://jeanmcdaniel.wordpress.com/