Sorry, there is still no plan to support UProceduralMeshComponents in this way. Without an underlying UStaticMesh, none of the export/merge tools work, and it’d be a large undertaking to support this in the future.
If you want to export procedural meshes, I’d contend that there’s probably a better way to do what you want to do, maybe building the meshes procedurally in your content creation software and importing that into UE4. In general though, I can’t think of a really useful reason to be able to export procedurally generated meshes to FBX.