That's a great list, TragicClown.
Anything by Eisenstein and Dovzhenko (like "Earth"/Zemlya) is good and famous. Aleksandr Nevsky (Eisenstein) is excellently shot and has a great score (Prokofiev,I think).
"The Cranes are Flying"/Letiat Zhuravli is a wonderfully shot movie about a wartime romance. A sort of pre-Private Ryan Soviet version of war films is "Come and See".
Aelita, Queen of Mars isn't very good, but it's funny
Try searching Amazon.com -http://www.amazon.com/exec/obidos/tg/browse/-/284938/ref=br_dp__4/102-0990561-3637719
I know "Russian" film doesn't equal "Communist" film, but there are some wonderful movies out there. Andrei Tarkovsky has made some wonderful more modern films in the 'Russian' category.
And Good Bye Lenin! isn't really pro-Communist, but it is a very good film.
I can't recommend "Children of the Revolution" though =(