Um, David, did you know that Leitz made a range of Summars for photomacrography? And a fixed aperture 25/2.8 Summar for a projection microscope attachment for some of their Prado projectors?
I have one of these last, asked about it on usenet shortly after arrived. The reports that came back were that it was a first class dog. Tried it out later, its actually a little better than a 25/3.5 Luminar, but only at much higher magnifications than 25 mm macro lenses are usually optimized for. Makes sense, given its intended application.
The other photomacrographic Summars are supposed to be a generation behind, e.g., Photars and Luminars.