It's a nice thought, but it's hard to see the business case for Autodesk...support for two platfroms in order to cannibalize their own sales doesn't make a lot of sense.
Also, in my experience, most engineers who use AutoCAD use at least on third party domain specific plugin. If those plugins aren't also ported then they still won't be able to move to Apple. In fact I know many people who would be happy to give up AutoCAD for something else, but can't because they need certain plugins.
