Attaching data in other forms

Issue following up from an email conversation with sdrycroft. This issue touches on two things: lack of documentation, and adding possible extra features. Time permitting, I'm happy to contribute to both for incorporation back into the module.

The site I'm currently working on needs two Google Maps related features:

1. Logged in users can see a map of their local region (on relevant pages), and add markers to it with extra info attached (spec undecided, but will probably include things like date and freeform text).
2. Anonymous users can see a world map (intl visitor) or UK map (UK visitor), with count(r)y boundaries marked in an overlay. Clicking on a count(r)y displays an infowindow with statistics for the count(r)y, which are generated from the data collected in (1).

Obviously some of this will lie outside the intended scope of the gm3 module and will require a custom add-on module to be written (if I can get clearance to release this, I will, in case it's useful to others in future). I think some of the features I need would be useful to a lot of people though. These are the key features I would like to see:

1. Ability to embed an empty map and configure it (e.g. size, default zoom, centre, terrain/satellite/hybrid). At the moment I'm working around it by creating a map with a tiny rectangle in Antarctica, where no one will notice it. Changing any of the options seems to require changing the gm3 source though.
2. Ability to attach a KML/XML file with region data for overlay. Examples of the type of things I'm hoping to achieve are at http://pages.towson.edu/preese/av/multiple_polys_from_xml.html (XML, APIv3), http://www.icgg.org/corruption.cpi_2008_worldmap.html (KML, APIv2) and http://www.geocodezip.com/geoxml3_test/v3_collection-map2e.html (KML, APIv3). Currently I'm using a custom module that includes its own .js and .kml file, which looks for a map on the current page and loads the KML overlay if it finds one. However, this doesn't allow control over which KML file is loaded for different pages/maps, and requires the module to be updated if the KML data changes. *
3. Ability to associate data with a map point, such that it can be accessed, not only in association with the point itself, but also in aggregate.
4. Documentation! I know the Google Maps API reasonably well, but figuring out how to "Drupalise" it and use it with this module is not obvious to me.

* I know that attaching region data is already an option, but lack of documentation and familiarity with the standard in question means that it's nigh-on impossible for me to figure out how to get data in a suitable format into the database. KML has a number of conversion utilities and assorted documentation and demos. At the moment I have a very rough demo up at https://secure.kitserve.org.uk/gm3/ although this link will probably disappear at some point.

Hopefully we can get a dialog going on these items and get them incorporated into the module.

Thanking you in advance!

(Edit: just noticed that some of these features are duplicates of other requests...)