If you want to do research, the DO/PhD route may be for you. Don't do it if you aren't interested in the research, though, because you give up quite a few years in the process.
Many combined programs do give you a stipend and scholarship, but in the long run you may be financially better off getting done years earlier and having a surgeon's income.
Its all in what you prefer, though. Where are you looking at? I don't know of many schools with DO/PhD programs...although I'm at one that has one.