I'm not a portrait shooter, but I have a Bronica SQA that will focus down to 1:1 with the 110 mm f/4.5 macro lens. In the Bronica line, the 180 mm can focus closer than the 150, but I think the 150 is popular for portrait work. Compared with run of the mill 35mm lenses, non-macro MF lenses don't focus in very close, maybe a meter is about it, more like 1.5 with the 150.
That said, the Bronica sells at fairly attractive prices, but is something of an orphan these days as far as service, as they are no longer made. There are currently some places that repair them, but it's anybody's guess how much longer. I like mine!