I think micropropagation could be really interesting, especially for citrus. However, it does require extensive equipment. Furthermore, you can't really determine if your propagated plants have a juvenile phase or not, which means you should base your method on work that was previously done (or be patient).
I was also wondering if it could be useful to graft citrus seedlings? I have some experience with in vitro grafting of tomato, and the protocol is very straightforward (if you have the right equipment). Would grafting citrus seedlings give the same benefits as grafting rootstock with scion? Any experiences?