No experience, I'm afraid, but the information on the Citizenship FAQ section of the German Embassy website in the UK (http://www.london.diplo.de/Vertretun...FAQ-Seite.html
) is not encouraging:
"I am a German citizen married to a foreigner. How can my partner acquire German citizenship as well?
"... Naturalisations whilst residing abroad are only possible in few cases; the requirements are strict and according to the Federal Foreign Office’s experiences very rarely met.
"Among others, the essential requirements are thorough knowledge of the German language and strong ties to Germany. It must be ensured that the applicant does and will not rely on public funds. Furthermore, the naturalisation must be in the public interest of the Federal Republic of Germany. Solely private reasons, such as the fact of a marriage to a German partner, usually do not constitute a public interest.
"Please refer to the competent citizenship authority, the Bundesverwaltungsamt (Federal Office of Administration), for further information (in German)."
My German isn't up to investigating this further via the Bundesverwaltungsamt website, but it looks like that would be the place to go to determine how these -- apparently quite exceptional -- naturalization from abroad cases are assessed and decided.