Logzor, how important is the built-in motor for you? I'm sure you already know, but macro work always involve manual focus and tripod. Always. Right now, there are only 4 macro lenses that have the built in motor.. the new Tamron 90 Di-II ($499 and hard to find), the Sigma 150 ($700 - excellent lens with great working distance), the Nikon 60mm "G" ($550 - good glass, but too short) and of course the Nikon 105VR ($900 - too expensive IMO). If you can't find the Tamron 90, the Sigma 150 is a great macro lens and in fact has been generating a lot of rage in the NikonCafe recently.
The Tamron 90 is a great portrait lens (very sharp with super creamy bokeh) but with one caveat--- it's not "fast enough" when it comes to autofocusing. It even hunts frequently. From what I gather, ALL macro lenses are like this by nature of the design.
I think the reason for the shortage of the Tamron lenses is due to the fact that the new model is coming out (the Di-II) and they are not producing the old model anymore. Regardless, if you come across any version, I'd say snag it. Just upgrade to a better body with a motor later on. (like a D70s or D90)
well, good luck..you'll find one eventually, just keep looking.