With this comes the idea of how such units could be used to rework the prototype system. Prototypes could be still limted as they are, but rather than just keep a very limited amount of replacements to use, maybe give an option to un-prototype a design like this at the cost of extra prestige, while limiting them to just one unit? Think about it as a general influencing the industry to keep the production running for equipment he finds useful on the front. It would not be mass produced, since only this one general finds it useful, but with enough connections he finds the way to get that gear. This would make them more interesting to use, allow to place them at fun points in the campagins and feel more uniqe. With Germany, it's mostly the endgame units such as Do 335 or the Maus tank, but Soviet AA guns are this early/mid war example that brought this up in my mind.
Also, the image of starting the German 1939 scenarios with the option to have a He 112 squadron in addtion to the usual Bf 109 seems really fun.
