Can you please elaborate on the 65000 Euro "green card"? I have been looking for a way to move to Berlin for many years, and have never come across this.
Yes, it is actually this simple: Find someone willing to hire you for 66000 Euro or more yearly salary (65 above was wrong) and you will get a working permit without much problems. The "only" problem is to find a job paying this salary.
In the middle of the page, "Hochqualifizierte (§19 AufenthG)": Highly qualified people like scientists, technical specialists with a wage of at least 66.000 € can immediately get a work permit.
Unfortunately that portion of the site hasn't been translated to English yet. Use Google Translate or call the BAMF for help.
An EU-wide effort called Blue Card is also on the (legislative) way.
The possibility that getsat mentions in a sibling comment to this one is described at the bottom of the page under "Selbständige (§ 21 AufenthG)". This possibility actually refers to founders of a company, the one described above is for employees. It's not 500 k€ though, but 250 k€. Still a lot of money. :(
I would be delighted if this is the way!