Combining attachments for user-created variant?

Given that the aircraft models now consist of multiple submodels and attachments, has anyone already found a way or can point me towards one to recombine those attachments/cabin variants etc. to new variations?
For example:

  • Adding the cargo pod to the skydive version
  • Having the handles of the skydive variant and a proper rear door with a passenger cabin
  • The passenger version, but without the pod