Crazy, but WORKING solution (hack)
Well, once PhoneGap 1.0 is provided as compiled lib, we can try to change the compiled binary itself.
The reason of Apple reject are calls to [UIDevice uniqueIdentifier] method deprecated in iOS 6. If your app (JS code) does not use UDID provided by PhoneGap (actually, have no idea is there a way to get it), it's safe (!? see NOTE bellow) to change the call of uniqueIdentifier to any other method returning NSString of UIDevice class.
I've used +(NSString *)systemVersion - getter of systemVersion property.
So, get any HEX editor and open file: /users/Shared/PhoneGap/Frameworks/PhoneGap.framework/PhoneGap replace uniqueIdentifier with systemVersion\0\0\0.
\0 - are zero code bytes, needed to align the length of new name which is 3 bytes shorter!
Rebuild your app, and… viola upload to AppStore succeeded!
NOTE: Sure, you MUST check your app functionality not broken. I did for mine app and it works like a charm.