You can also buy the Limited Edition (if there are still copies available... after all, it's limited!) there
The Limited (Deluxe) Edition of the game and the Collector's Edition include the same disc. It's just the physical bonuses that come with it that make the Deluxe Edition what it is.
As for an edition with German language on the box and in the manual, you will have to wait until a possible time when a German editor picks up the publishing rights for Germany, like Daedalic Entertainment did for Tales of Monkey Island