Over the past years the portraiture business has been discussed in various forums, by wanna-be's, the been-there-done-it crowd and pro's. I would suggest that you read a few just to educate yourself.
For an existing film shooter, starting with MF for portraiture I think would be the best way to go. You have a right side up image, reasonable prices on equipment, easy smaller kit for outdoor enviromental portraits and lot's of film choices, for now. Digital backs are available if you can afford it. Roll film in b&w is easy to develop and scanners can be had that do a good job. An RB would be a good studio camera that could also travel. I have one for sale btw; (Shameless plug.) Overall, and this is just my personal opinion, why not just get a film camera and use it to shoot with. Experiment with it and see if it's your forte. If not, you've not spent alot of money, and could turn over, say a Rollei TLR pretty easy, as compared to alot of other MF cameras and systems. MF systems are cheaper now because their not the most popular items right now. We all love film here and hopefully you'd come to love it too, but each to their own. I say shoot some film and quit looking at the LCD for awhile.
For an existing film shooter, starting with MF for portraiture I think would be the best way to go. You have a right side up image, reasonable prices on equipment, easy smaller kit for outdoor enviromental portraits and lot's of film choices, for now. Digital backs are available if you can afford it. Roll film in b&w is easy to develop and scanners can be had that do a good job. An RB would be a good studio camera that could also travel. I have one for sale btw; (Shameless plug.) Overall, and this is just my personal opinion, why not just get a film camera and use it to shoot with. Experiment with it and see if it's your forte. If not, you've not spent alot of money, and could turn over, say a Rollei TLR pretty easy, as compared to alot of other MF cameras and systems. MF systems are cheaper now because their not the most popular items right now. We all love film here and hopefully you'd come to love it too, but each to their own. I say shoot some film and quit looking at the LCD for awhile.