What I mean is, there is NO Lufthansa Worldshop in Cologne. So there is no way to buy the Lufthansa Collection Suitcases in Cologne.

A Cologne comedian called "Den Dom" once "big church close to McD", that's where I picked it up

I priced Rimowa all over SE Asia (Bolero carry-on) including Hongkong where I currently live and no, Germany is by far the cheapest place so far.

There is a Rimowa store right in Tsim Sha Tsui and if I recall correctly, the Euro price was three digits more expensive than in Germany. In Beijing one store even asked for something like 700 Euro for a suitcase that prices around 300 Euro in Germany

Didn't see Rimowa in SIN but I am sure you can get them, I just don't know the price.