Why not still keep it simple with multiple training databases. So, keep Northwind as a general database. Then you can have one simple database that shows how to use analysis services - and it would be built with just SSAS in mind. Then have another one for spatial data, etc. They could still be small, simple and concise - and used for specific training purposes. Why does it have to be one huge database that covers everything?
Mia
I have come to the conclusion that the top man has one principle responsibility: to provide an atmosphere in which creative mavericks can do useful work.
-- David M. Ogilvy