I am looking to JB then Unlock, but I guess not. I was looking to do this only because I would be out of the Country and was hoping to get a local SIM where I am going, but I guess I will have to buy a cheap phone for AT&T then.
like I say even if you had your SHSH blobs saved so could go back to 4.0.1 or 4.0.2 then you still couldn't unlock as your baseband will be the latest and that cannot be downgraded.