A few rose growers.

Rosa Plaza is a group of growers that auction under one name with a wide range of varieties. Very informative site.
http://www.rosaplaza.nl/

Wim Ammerlaan. Farms in Holland & Ethiopia
http://www.wimammerlaanrozen.nl/EN/index.htm

Porta Nova. Top quality Passion grower. (English site under construction)
http://www.portanova.nl/portanova.htm

Van der Weijden. Ilios & Trixx grower
http://www.rozenkwekerij.nl/en/profiel.php

Botanic roses. Tenga Venga, Himalaya & Pura Vida
http://www.botanicroses.nl/English/newcostarica.htm

Illusion roses. Caroussel Illusion, something a bit special.
http://www.illusionroses.nl/ENG/default.htm

Kordes Roses. One of the biggest in rose cultures.
http://www.kordes-rosen.com/

Roma Rose. A spray rose grower. The site is in Dutch, but all varieties are well presented to show their colours.
http://www.romaroos.nl/

That should keep you all going for a while.

Gringo.