You can pick one up from ThinkGeek for $50 (if they ever get them back in stock)
I could have sworn my dad had a Rotring pen with the same action 20 years ago. At that time it was just considered a pen though, and not re-branded to be “tactical” in order to sell a million of them to COD and Airsoft nerds.

I wouldn’t buy 99% of the stuff on ThinkGeek because collecting random crap is not something I do. There is that 1% of their products though, that are so clever I almost want to buy them.
Hat tip: Steven, Blair
Thoughts?