There is even a little more convincing alternative in BW (the PBC has its main base as well in a BW, and I think there is even a small village, where they have the majority), but they are as well far below any serious level in non-regional levels.
The ökologisch-demokratische Partei.
On the local level there is often some kind of free-voter-party alternative, but they have usually no all over the country presence, which makes it nearly impossible for them to enter any parliaments. For a new party to enter there has to be a huge movement (greens) or a otherwise dramatic historic event (Linke, if you assume that the WASG would have had a hard time without the PDS party apparatus).

And indeed I think that the CDU will not take its "Leipziger Parteitagsbeschluesse" very serious. In 2005 the CDU ran a full economic free market campaign (as you probably know, but maybe accidental readers not) and the outcome was much worse than expected. We have grand coalition now, so CDU and SPD can't go completely in different directions on the issues, but I frankly don't see on which substance CDU and SPD will run their next campaigns as probably no party will explain that the current period was a complete waste of time and after all the politics was as well not so incredible different from the red-green gov under Schroeder (Can anybody name something significant happened during the last years, else than the VAT increase and some family policy where the CDU minister did a pretty much SPD like policy?).

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers