I happened to see this pen on eBay. AFAIK, there is no information available on this pen.

According to the original description of the pen by the seller,

"...Made in Germany during 1936 ONLY in this exact form. This wonderful Pelikan 100 is VERY rare indeed. It has several UNIQUE features that separate it from ALL other models 100 and 100N. Firstly it is the LONGEST model 100 ever made aside from the equally rare 1936-37 Magnum 100. However, a Magnum looks obviously different whereas this Black 100 looks like any Black 100 from 1930 to 1937 when capped unless you have a few other model 100 to sit it next to and compare length etc. This model 100 for sale is a beyond rare Transitional Prototype. It has design similarities to a 1st issue 1937 100N yet ONLY takes a model 100 Piston. Its Barrel is UNIQUE as is its Black Binde. (Longer than ANY other 100. See photo 5). This pens barrel resembles a 1937 100N however it is NOT a 100N barrel. This pen shares far more in common with the Magnum 100 than the 100N. The pens front section (part you hold when writing) is again very similar to a 100N and is indeed unlike ANY other 100 you will ever see. That is except for the Magnum 100's front section which is also pre 100N and is from 1936 as well. See the bulge where it attaches next to the barrel threads. Notice how this rare Transitional 100 has a bigger wider bulge than the 1937 1st issue 100N or ANY 100N for that matter. It is more similar to the Magnum 100 front section bulge (see photo 7). Also this pens UNIQUE front section takes the Nib and Feed direct (Push In) like ALL Pelikan 100 from 1929 to 1937 whereas the Pelikan 100N from 1937 up to Present day has a Screw in Nib/Feed assembly. Even the model 100 has screw in assembly after 1937. The Magnum 100 was the 1st pen Pelikan made to have the screw in nib/feed assembly. This pens Piston and Barrel can ONLY take a model 100 (1929-37) type Piston. The Barrel threads and diameter of the inner barrel are UNIQUE in size to early model 100. A piston from a 1937 onwards 100N does NOT fit this ULTRA Rare pens barrel. A 100N piston has wider parts than a 100 piston and the threads of a 100N are wider diameter and different thread count etc. It is not even a close fit (see photo 7. Of course a Pelikan 100 Piston does not fit a 100N either).

So, although this pens barrel and front section look like a 100N they are in fact a 100% Pelikan Factory original Prototype model 100. VERY few of these were EVER made. It is the first example I have ever seen. These NEVER went into standard production. However, this pen is unquestionably the missing link between the 100 and the 100N. This is the pen they first designed the barrel and front section on that later became the 100N.

Another UNIQUE feature to this transitional 100 is the Cap diameter and Caps Top Section. The cap is also a unique size as are the Barrel threads. No other Pelikan 100's cap from 1929 to 1940's fits this prototype barrel. Standard Pelikan 100 caps do not even get past the front section let alone near the threads. The barrel threads diameter is TOO wide for a standard 100 cap. Only Pelikan 100N caps are this wide. So we have a barrel that ONLY takes the early 100 piston type and at the same time only takes 100N size caps. As such the cap does not fit tightly on the tail end when posted ready to write. which is a good thing as it prevents cracks. The cap screw onto the barrel threads perfectly as when new. Tight and secure. This pens Cap Top Section is equally unique in that it has the Early pre 1938 Pelikan Nesting Logo and Pelikan PATENT side imprints like ANY 1929-37 Pelikan 100 has. However this pens cap top section does NOT fit ANY model 100. It is TOO big. The tread diameter is too wide for a standard model 100 cap. ONLY 1937 model 100N have top sections with this diameter threads. But they have D.R.P. imprints. Making this UNIQUE top section a first of its size ever made. Can only date 1936 possibly early 1937. Making the cap original to the pen. Once again this pen is NOT a 100N nor is it a standard 100. It is a transitional prototype bridge between the 2 models that can ONLY have happened in 1936. This pen is very rare indeed..."