Seems like you are somewhat poorly informed. Zeiss glass in Minolta/Sony A-mount is made under direct supervision of Zeiss, by Zeiss trained people, with special Zeiss equipment and Zeiss quality control. Such lenses have two serial numbers: a Zeiss number for the glass and a Sony number for the entire product. These Zeiss designs have been made newly and are exclusively available to Sony. So they are not the same as some designs available in other mounts and of course they are AF/IS. Of the cheaper Sony lenses there are some that appear to be the same as Tamron, but these are not interesting to you, based on your demands. The lenses you would need are apparently all made by Sony -former Minolta- in their own factory. Minolta used to have their own glass production which allowed them to design very exclusive lenses, like the 35mm from which I showed you a picture.
Regarding the quality of the Hasselblad 28mm: it is not an extraordinary design at all. It's just that Hasselblad has incorporated specific digital corrections through software. If you want really outstanding glass for medium format then you should look at Zeiss lenses as they were made for Contax or Rolleiflex, or have a look at Schneider lenses for Rolleiflex if you want to be in lens-heaven.
Interesting. That's the thing with the web, lots of information out there, but trying to sort the wheat from the chaff is not easy. And forget the days of having a nice leisurely chat about equipment with your local friendly photo dealer, they're all on the phone doing eBay and web sales.......
You are probably right about the Zeiss glass (I really don't know), but for me the problem is how much time do I invest in researching out the equipment and then sourcing a couple of pieces to test, when I know that both Nikon and Canon have equipment used and tested by pros around the world. Nikon and Canon are the industry standards, just as Hassy and Phase One are standards in MF, Sinar in LF and Profoto in lighting. That's why I think the Sony's will become a much stronger brand worth considering (for me) in a couple of years time. Personally, I'm not ready to be an early adopter, it doesn't work with my business model (which requires access to rentals and backup gear thru CPS etc). When this recession turns around, maybe I'll get one as a backup camera to test, but not right now.
Contax lenses, oh yeah. I loved the Contax 645 and a Phase back set-up. Beautiful. For me some of the best lenses for that intangible feel in MF are still the RZ's though - technically people can crap all over them, but they have a feel on film that is - IMO - unmatched. It's such a pity they can't be used with a digital back without losing that quality (which needs to be seen frame edge to frame edge), but that's a whole other discussion........