[MartinMond]

I've just talked to esad (he's sitting right next to me at the local cocoaheads meetup), what the component does is use a separate R-Tree like data structure to keep track of MapView annotations and perform clustering/display and it seems to deal fine with ~50k annotations on an iPhone 3G. Esad's using this in his local search app http://www.oeffnungszeitenapp.at/