Why thank you very much, IBC; it's always nice to get a compliment from you regarding Russia!
As for your own theories on how Czecho-German relations could develop, I must say they are top-notch!
I do wonder, though, how a Red Germany would treat the Danzig/East Prussia Questions. And on that note, how would German-Polish relations develop if Germany goes Red?
You could have an interesting clash within German politics between German nationalists/irredentists on the one hand, and those willing to co-exist with Poland and abide by Versailles (or at least not be militantly opposed to it) on the other. (Of course, this could also have a lot to do with how the Czech situation works out.)
But there will be no Versailles in this world: the Reds presumably come to some sort of armistice with the British and French, but they're going to be less willing to be dictated to as to what their eastern borders are going to be.
Additionally, is there a possibility that we could see a German-Polish alliance to counter a potential Russian threat? Or even a German-Russian alliance to curb Polish ambitions in Central and Eastern Europe? (I'm a bit doubtful on the last one unless German Communism heads down a Stalinist path.)
I'm not sure why Polish power in eastern Europe will be more powerful than OTL: unless the Whites come to power after a period of well, warlordism, it's hard to see Poland pushing much further east than OTL. As you say, it's hard to see Germany and Russia coming to a split-up-Poland arrangement ATL: I'd consider German grudging support for the existence of Poland likely, since 1.) after the Revolution, Germany is in no real shape for military adventures, 2.) Working out a peace with the Brits and French is going to be hard enough even without going all March-to-the-East on the Poles, whose independence French and British are probably going to be favorable to (swallowing the Czechs is going to aggravate them as it is) and 3.) the further east Poland extends, the further away and weaker the Russians are.
(Hm. Possibility - the Germans trade support for Polish expansion to the east in exchange for a link to east Prussia. This puts Poland in Germany's debt, and worsens Polish relations with Russia - forcing them to rely more on German support. Also, a larger Poland may actually be a weaker Poland, suffering from serious internal divisions...)
Bruce