Where did you find that lens? I've been looking for something like that for a while now for my D90. The Nikon lenses are nice but I have been longing for some older lenses cause they usually have much better optics in them.
How do you like the alphas? I want to get into the micro's but till canon makes a real one I'm not jumping on board. I had a J1 for a while cause my 3100 fried and I wanted to kill someone that was a real piece of shit.
I bought it off Adorama. Some other good sites are
www.keh.com and bhphoto. Key prices their used equipment a little higher but they've got a great collection.
About something for your Nikon, that's a bit tough. Basically Nikons are unable to take adapted lenses without actually physically changing the mount. With the NEX you're able to use an adapter. This all has to do with the sensor to mount distance. The NEX series has a short distance, the Nikon a prohibitively longer one.
With that said you can still adapt old school Nikon AI and AIS lenses. There are a couple of gems that can be had on the cheap like their own 28mm f2.8 AIS Nikkor, and the 105mm f2.5 AI which is an amazing portraiture lens. There are also some cheap but great, optically, 50mm lenses to find. So my suggestion is to look at these vintage Nikon lenses.
Not sure if you've played around with focusing manually and using a physical aperture but look into if your camera body can accommodate these old lenses and if it's good for manual shooting.