merging two identical databases

Hi there

Just wondering whats the best way to merge two user databases (identical schema but different data) ?

This request came when two of our clients merging their businesses and they want to combine their databases too. 

I already checked import/export database wizard and it does not appear to be the tool for the job so current plan is,

we use identity primary keys so Set up all foreign keys so that ON UPDATE CASCADE is set and Update the Primary Key  in the parent table and add the max value of the field of the destination database table and import.

we've hundreds of tables so want to check if there is a better way to do this BEFORE i go down this path.

Thanks for the advise. BTW we use sql server 2008 r2.

prk