Thanks to Alex Moore for pointing me at this one. Nope, Alex it wasn't the one I was thinking of but this is great nonetheless :-)
Wow, and on the same theme thiese guys have provided a serious list of vector logo sources: http://www.brandsoftheworld.com http://www.Logotypes.ru http://www.logotypes.lv http://www.lalogotheque.com http://www.fcklogo.com.ar http://www.portalpublic
...and how did I not know about this? I have wanted this type of resource for years. I've been finding colours in nature, photographing them then sampling in photoshop. This makes life a looot easier...