Danish kroner is on of the most stable currencies in Europe...

For now... I said, when the financial mob would look for new victim. I lived the euro crisis from close by and watched the local financial TV channels in Japanese. I got quite upset on how ignorant they are on Europe and the fundamentals. Don't forget the Eastern markets set the tone for the rest of the day since they are first to wake up. If it happens, a small currency has no chance.

A better argument for not placing it in Denmark would be the tax on the payouts, and here I don't know about the exact rules.

Scandinavian countries have the reputation to have the highest taxes and wages in the world. The currency should be USD or EUR, but ideally in a lower wage country since you'll need a local bookkeeper to comply with the local laws. Our friends from DepositFiles/Photos showed the way: Cyprus, or Ireland. You'll need expert financial advise though, on the best location for a coop that has members from all over the world.