There are several great breeders in Texas; you should try going to some dog shows, or competitions (Schutzhund, Rally, ect.). I don't really go to events very frequently, but I know they are always having "shows/events" at the Triple Crown club(?)
http://www.triplecrowndogs.com/142/Events.htm here is a link to there "events" page. It wouldn't be too far of a drive, and you might get to see some rotties you like
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Even if you don't find a dog in Texas, maybe at least get one a little bit closer than Germany...this way you could meet the breeder.