I will happily second the recommendation (based on my visit about 2 years ago, at least) and agree 100% with osch's review.
If you are in Berlin, Mercedes should be number 1 on your list. Number 2 should be Ria at
www.vankampenberlin.de (also a thread in this section of the board) - the few reviews of her on German sites are admittedly mixed, by my personal experience with her was very good! Joyce at Van Kampen surely also merits further investigation... Then take a train ride to Hamburg and visit Chanel (search on
www.modelle-hamburg.de, also previously posted by me).
Eager to get back to Berlin soon!