I'm generally happy with my Monochrom (having an extended holiday in Wetzlar) and my SL (with zooms and M lenses). However, I did want a smaller camera I could put into a pocket.
The Summaron-M 28mm, even with the M-Adapter T, makes for a compact camera with equivalent field of view of 42.5 mm (in 35mm terms). This also reduces the softening of the edges of the image and vignetting.
Please excuse the crappy iPhone photos.