According to my research, Your specific camera S/N
1136106 was produced in 1965 in a production batch of 500 cameras. A total of 3316 MD's we're produced between 1963 and 1966 and assigned S/N's
1102501 through
1160820. It appears it is a rare camera. The next model in that line was an MDa which had a production run of 14,500. The MD has no viewfinder or rangefinder. While you can use it for its original purpose with a microscope or telescope, the more contemporary use would be with an ultra-wide angle lens such as the new Voigtlander 12mm, 15mm, or 21mm lenses. These lenses don't need to be rangefinder focused. There's a small slit on the bottom plate that allows you to insert a thin transparent plastic information sheet before exposure. If you're photographing slides and want to record what you're documenting, you can write in on the info sheet and insert it
It was manufactured by Ernst Leitz Wetzlar in Germany, has a Horizontal cloth focal plane (1 sec - 1/1000 sec shutter speed and flash syncs @ (1/50sec)
External cold shoe M- and X- flash cable connector on rear. It uses standard 35mm film and it's physical specs are Body: 138mm x 77mm x 36mm; 595g.
I tracked down camera S/N
1136470 which was 364 cameras after your camera's production. It appears to have been sold in 1998 by Christie's of London for $1874 American. I included a link to the auction below. I'd say your $25 investment was VERY good! Hope this helps. Good Luck.
Leica MD no. 1136470 | Christie's
It appears you may have some winners in the lenses as well. For the one you photographed holding, I found the following comp on ebay. By the way, The leitz summar lens you have is attached to a summar adaptor. It's the outer ring imprinted with 24.35.42u.50
Ernst Leitz Wetzlar Summar 24mm lens for micro work | eBay
And again here's another link to a page that sells summar lenses like your for $300-400. They have alot of lenses listed on the page along with enlargers, copy systems and such. Just scroll down to find your lens style.
copy.htm