I have updated the tool described in this article with some new functionality.
Download the script from the above referred article. Create a Lookup column in your list and have it point to the actual list it is created from (it is in fact not relevant what list you point it towards). Load the script from the above described article and select your list:
Select the list
Modify the web and list association and hit “Save”:
NOTE: The web selector is only available for site collection administrators.
If you are a non site collection administrator, you may change the list association, but not the web association.
This method requires NO modification to the field schema and is fully compatible with Data sheet view etc.
I have not had the chance to test it in SharePoint 2010 yet, but i can see no reason why it should not work.