I applied for my "Beibehaltungsgenehmigung" in August of last year and was approved 4 months later.
Here's my timeline:
08/03/2009 submitted application to German consulate in L.A.
09/01/2009 the Bundesverwaltungsamt in Cologne received my application
11/20/2009 approval letter was issued
01/29/2010 picked up certificate at German consulate in L.A.
By the way, I did not hire a lawyer and handled all the paperwork myself. My ties to Germany: family, friends, regular trips to Germany, German bank account, German high school diploma, MA degree from German university. My main reason for becoming a US citizen: I'm an only child and will either have to sponsor my parents in order to take care of them or will have to move back to Germany for an extended period of time (both scenarios would require me to be a US citizen).
Good luck!
Silke got a reaction from msdynamite in Dual American/German Citizenship (Beibehaltungsgenehmigung)