I do not have a lot of time to surf around 
but I would like to recommend a few sites 
which I think are worth some of your time too. 
I hope you will enjoy  " mes favorites":
      
Friends
The      Allegri String Quartet
Sebastian      Huydts
Willem      Jeths
Caroline Ansink
Mieke de Waal
Judith van den Akker
Harry Sparnaay     
Rian de Waal
Flamenkika
       
Companies
Brabantkoor en Brabantorkest
De Nederlandse Opera
            

Interesting Links
Opera Trionfo
Classical Music UK
Classical Net
Klassieke-Muziek.Pagina.nl
Dutch Divas- In Opera & Concert Klassieke Muziek.opzijnbest.nl