This one could be considered a copy, but is not cheap at the moment:
Platinum Knock 18, from 1965.
Follow ups to that daring statement dealt with the morality of counterfeited goods. Now, I wanted to add some more information.
This is one of the first Pilot patents about the Capless pen. It dates from 1964 (published in 1966):
This one is a patent of a very similar idea, but from 1944 (published in 1946):
Which copies do we accept as legitimate and which ones are not legitimate?
For reasons nobody explained, that original thread was locked.
Edited by Iosepus, 02 September 2010 - 17:53.