Hey Rat,
Its' been a couple of days since I checked in here...sorry for the delay. I tried a ton of things to create the carve for my LP. I finally ended up making a bunch of individual surfaces. I'm not sure how familiar you are with surfaces, they are a little different than solid models. Surfaces a created by creating a 3d wireframe, or the 3d boundary of an area. If you look at the lower bout area of my LP, it is made up of 2 surfaces. One on the left of center and one on the right. The boundaries for each surface are the center line, the outside contour of the guitar and a horizontal section that creates the top of the surface. The thing is, none of these boundaries is flat. The vertical center line looks flat from the top view, but from the side it is a curve that runs from the high point of the carve down to the outside edge of the guitar. This is really hard for me to explain without some kind of visual aid. If you still have questions I can take some screen shots from my drawing or I might be able to make you a .stl or Iges file. Let me know