Vladimir,
I wish I could tell you where to look for one, but they do not turn up very often. The 1908 is difficult to find and the 1906, either original or re-barreled, is almost impossible. Watch the major dealers - Simpson, FGS, Bob Adams, etc. - Gunbroker, major auction houses like Rock Island or James Julia. It is just a matter of patience as they are pretty scarce guns, particularly all original. You frequently find guns with Bulgarian parts like the one we have been discussing, but complete guns are very difficult.
Here are my two examples. The 1906 was rebarreled when the 1908 9mm was adopted.
Ron