Russia
Only kennels whose own sites say they breed Mittelschnauzers and give a city are listed. Ave Concorde’s site did not open (it showed an unpaid-site notice), so that kennel is omitted.

Pepper and salt 
Black 
Standing
-
Trels
Moscow Kennel Trels -
Rus Rastr
Moscow Rus Rastr contacts -
Alpen Trevel
Saint Petersburg Alpen Trevel
Trels states that it breeds only pepper-and-salt Mittelschnauzers on trelsgelis.ru/kennel.php. The Moscow line is the litter place on the kennel site linked above. Rus Rastr’s contact page also names a Nizhny Novgorod branch. Alpen Trevel’s page says the kennel breeds only pepper-and-salt medium schnauzers and names Saint Petersburg.