I have a Pfaff2140 embroidery machine upgraded to 2170. I bought 4D Extra software so I can create my own embroidery and quilt designs. I can draw a design, scan it into my computer, then download it to my Pfaff and quilt. The software has a 'Trace' feature that turns an embroidery into an outline. Wonderful for quilting.
An example: last summer I made a scrap quilt with 2 different Kitty blocks for my DD and family. For the border, I designed a repeating outline of a mouse to quilt. Haven't done the quilting yet, because the quilt is in NY, the 2170 is in CT, and I'm at our winter place in Tucson. When I finish quilting it this coming summer, I'll post a picture. I bought the 4D software specifically for designing quilt designs. You can also use it to scan and use un-copywrited designs in books and magazines. It's wonderful!
I agree that embroidery is so dense that it's better to do it BEFORE quilting. The quilting I do is OUTLINE designs.