Content is tied to the Apple ID that bought it. This has always been the case since the inception of the iTunes Store and Apple ID's.
I'm not entirely sure why anybody thinks buying a new device means you need a new Apple ID.
When you set up the new device you can use the same Apple ID to set it up and keep all your purchases intact.
I too want to be able to do this as I have an Ipad2 I want keep all the games I have bought for my son on whilst I migrate my usage of the Pad onto a new retina (ipad4) device. I don't want to have to setup a new account for my device as I want access to all my old productivity apps etc. and I don't want to have my old pad tied to my previous payment details.
You don't have to do any of that.
You can keep your old ID, and update its payment details and email address as you see necessary.
You absolutely do not need to create a new one. Nor should you ever want to create a new Apple ID just for a new Device.
Go to Appleid.Apple.com and you can manage your Apple ID there. Change its payment details to whatever you want, update its email address if required etc...
Then use that same Apple ID to setup the new iPad Retina and you'll keep all your purchased content.