Just wanted to update you with the latest info.
My battery consumption is normal again!
I reduced my 9 desktops to two empty desktops, then powertop reported normal values, dss and core wasnt ON anymore and about 75% in c4 state. So everything okay. Then I loaded an older backup with DesktopActivityManager with only some minor differences to before.
Then tried powertop again and my problem is still away!?
So Im happy with my n900 again!