This blog resumes my experience in virtualising Lion OS X and Xcode4 on Windows 7 64bit.
I would say that I easily achieved this objective following with this guide. My concerns were basically on performance; I configured my virtual machine as 2 double core processors with 2 GB of RAM and I was happy about them my Virtual Apple is really usable.
An other interesting configuration allowed me to use the Apple Wireless Keyboard (I bought it for iPad and I never needed it), in order to have a fully working keypad and using all the shortcuts that Apple Lion X has. I was really surprised when once I turned on my keyboard the Lion OS X detected it, but it was unable to pair the device directly with Lion; so I paired the Wireless Keyboard from Windows and used as alternative input device on Lion OS X.
Below some images of my new iMac and my first xCode application
Now I have the possibility to experiment xCode without buying a real iMac.