Research electives are a brilliant idea. Remember, you can go for electives usually only for a couple of months once you start your internship. And that would be once you are done clearing final prof MBBS exams. These days, a couple of months may not land you an LOR from the Dean of the program. You would have to work your behind off to manage that. Please don't get me wrong, people manage them, but it's hard. More often than not, clerkships in cores are tough to come by. Remember, most teaching hospitals have colleges attached to them. They have their students rotating along with students from other affliated med schools (most often the caribbean schools). Getting an elective or a subinternship in fields within primary care may still be relatively easier.
You would have to call universities and find out for yourself which places take people. IMO, it will be better if you start research within your college on sort after topics as well as get them approved by an accredited body like the ICMR (~india). Get actively involved in case studies on health issues in and around the city your college is located in. Work in domiciled schools goes a long way.