And first of all can I say thanks for a great plugin as it has given my site a real leg up in using Google maps.
I have a suggestion for an additional shortcode that I have implemented here and was wondering if you would consider adding it to the general release as I think it could be useful to many others. If it can already be done I apologise although having looked through the source for current shortcodes I couldn't see it.
The idea is that the placemark shortcode can accept multiple placemarks. Right now I have created a new shortcode add_multi that takes a comma separated string of placemark ids and when it loads it explodes them into an array and then outputs as placemarks in the normal manner. I am using it for a find nearest 10 placemarks to a location by querying the custom data type outside of the plugin and then passing the 10 I want via a do shortcode - seems to work quite nicely. I am sure that there are others who would find a use.
All the best