Excellent translation in my opinion, although I think 'Best Practice Organization' may be a compound proper noun in this context (see reference below) and should probably remain untranslated. In that case, the sentence would read:

"Internationale Best Practice-organisatie heeft zich ontwikkeld en uitgebreid tot een belangrijke kracht van wereldformaat"

or (not quite according to current practice for this kind of "mix", I believe, but perhaps somewhat clearer) :

"Internationale 'Best Practice'-organisatie heeft zich ontwikkeld en uitgebreid tot een belangrijke kracht van wereldformaat".

The term "belangrijke" could further be considered tautologous in translation (to a much greater extent than 'major' in the source text), and could be omitted.

http://www.aero.org/news/newsitems/bestpractice1-31-07.html
The Aerospace Corporation has been selected one of five “Best Practice” organizations for knowledge retention and transfer by the American Productivity and Quality Center (APQC) and will host an APQC benchmarking study Wednesday, Jan. 31, in El Segundo. The corporation was chosen from 49 potential “Best Practice” partners.