It never is mentioned when talking of portraiture, but I would recommend a MAXIMUM of 12mp for most portraiture. Ya see good portraits BLEND contours and tonality, unless of course you are shooting that old salt with 6000 wrinkles in his face.
Women especially like their pics to flatter rather than show every wrinkle or blotch. For studio work a good strobe with a big softbox will be right there second with lens choice. I second the Nikon line for an unmentioned reason. If you really stick to Portraiture and wedding venues, the Fuji S5 pro, {which uses Nikon lenses} might just be your affordable camera. Its a heck of a camera for those special uses.
I use Portrait Professional with my portraiture. It's very affordable and really does an admirable job even in the automatic mode. When I shoot a job with lots of different customers, {high school dances, etc} it saves the day because I can turn out lots of images with good results in a reasonable amount of time.
Just my humble opinion.