> Nevertheless, troubles arise if you have to query the historic > table, making joins with look up tables wich reside in the main > database.
A valid point of course, but not a problem in my case. I don't have that many lookup tables I'd need to be duplicated. Often enough I even don't need a duplicate lookup source, because my applications are the only accessors to the database, and so I can easily run a lookup against a datasource bound to a different connection (working with ADO.net, all the really interesting stuff happens in local RAM anyway).
