Just a quick note about a new SQL Server tool in search of beta tests. Perhaps you'd like to check it out?  Remote Keys allows you to define and enforce cross databases integrity constraint. With Remote Keys, you can create a foreign key between to SQL tables located in distinct databases.  Beta version can be downloaded here : http://www.remote-keys.com

I'm most familiar with enforcing foreign key constraints across databases by using triggers.  Perhaps Remote Keys offers a new way to do this? 

The tool's creator wants your feedback.  And I'd like to know what you think too.