Since your career interests include doing clinical work, it would probably be a good idea to directly ask about this for the joint social work and psychology PhD program. Those kinds of joint programs are often focused on training TT faculty, career researchers, and policy makers, with far less emphasis, if any, on clinical work.
I'm not in social work, but my understanding is that social work PhDs are more for research and policy anyways. There's also the doctor of social work (DSW) degree that's more practice-oriented, kind of like a PsyD for social workers.
Furthermore, a joint social work-psych PhD wouldn't really make you a practicing psychologist, the provision of your degree would be as a social worker. You wouldn't be eligible for positions designated for licensed clinical, counseling, or school psychologists, as you scope of practice would be different.
Thank you for replying! Part of the program is that you gain an MSW on the way to your PhD, which allows for more clinical application than the "typical" PhD in Social Work or Social Welfare. That said, it is a good point about not being a practicing psychologist at the end of the day and that it is (even more so than the stereotypical PhD program in Clinical) a research program. It would be more difficult (and you'd make less money) to go all the way through with a PhD, to just turn around and do exclusively practice after becoming a LCSW. That's certainly not (exclusively) what I would want to do.
Rather, I am envisioning a (very roughly and very preliminarily) 60/20/20 split between research/teaching/practice, which is why I think a children's hospital attached to a university would make sense.
Of course, if there is something I'm wildly not understanding, please throw things at me. 🙂 But also let me know if this response makes sense given your concerns.