It should be convenient to be able to add some bodies to the fins, for example such as the pods of the rocket shown here :
http://img343.imageshack.us/img343/9943/2189wilaxfrl64zh.jpg
or here
http://artic.ac-besancon.fr/Arts_Plastiques/07imnumeriq/ChappardFuseeTintin/AAA_Fusee_Tintin.jpg
Best regards
This would be better accomplished by general external pods. I've considered adding them at some points. However, it's unsure how these should be modeled. They might be modeled by extending Barrowman's method of bodies and add them together, but it's unsure how valid this would be.