Here is a retractable concept pen that Parker attempted to design, perhaps to compete with the popular Namiki Vanishing Point. This model was not finished.
Notice the Parker 75 nib being used, which is why I think it is a concept model for a retractable 75 FP.
At the Columbus Pen Show in early November 2004, I was presented with an object that at first glance was thought to be an odd-looking lipstick case with a pocket clip that resembled the Parker Arrow clip from the 1980s. :-) It goes to show you not to judge a pen solely by its exterior appearance.
One thing to note about the clip is that unlike the Arrow, this pen's clip is two-tone. The angled sides are silverplated while the center is goldplated. Arrow clips are monotone either as silver- or goldplated.
I slowly unscrewed the cap and, I got quite a surprise to see the nib extending from its retracted closed position. I believe this to be the finished version of the concept pen shown at the top of this page. To say that I was shocked is an understatement since I never thought the concept was taken any further!
Being threaded, the cap fits into threads that are exposed on the barrel via a spring-loaded back end.
Here are comparison photos with the sterling grid 75 FP. You will immediately notice that it is significantly shorter when collapsed and closed, while being longer with the cap posted onto the barrel.
The person selling this pen was a retired Parker employee who worked in product development so the 'provenance' on this pen is correct. It was definitely made at Parker in Janesville, WI.