Andreas: That Colpix company sleeve is a real rarity (in capital letters). You may want to send a scan of it to some of the 45rpm sleeve galleries that people use for research (as well as take some samples from their galleries for your design files — they’ve got lots of interesting vintage designs):
1. http://www.45rpmrecords.com/ms/index.php
2. http://crossedcombs.typepad.com/recordenvelope/page/1/
I don’t remember seeing a Colpix sleeve even when I was buying records here in the 1960s. I only remember brown paper sleeves for Colpix, and I’m in NYC where the label was based. Maybe the fancy sleeves were only for DJ promos, or during it’s later years when the company had few hits (the company had a short life in the 1960s).