It's not for sale but I have a Tamron S.P. 17mm f3.5 lens and I suggest if you buy one you ensure it comes with the dedicated lens hood which was an optional extra because the later of the two lens models the one without dial in filters has no filter threads because the filters screw into the outside of the lens hood http://www.ebay.com/itm/Tamron-SP-17mm-F3-5-Adaptall-Nikon-F-Mount-/132144118121
It's not for sale but I have a Tamron S.P. 17mm f3.5 lens and I suggest if you buy one you ensure it comes with the dedicated lens hood which was an optional extra because the later of the two lens models the one without dial in filters has no filter threads because the filters screw into the outside of the lens hood http://www.ebay.com/itm/Tamron-SP-17mm-F3-5-Adaptall-Nikon-F-Mount-/132144118121
My experience is the early (first) version is slightly sharper and less prone to flare and had the built in filters, mine was stolen. The second version d no longer had the filters still a nice lens though.
Also, I'm open to other portrait length macros, I have the Nikon 105 f/4 at the moment and, although I could be wrong, I think I could probably do better in the sharpness dept. I'm using it exclusively to digitize 35mm film.