Would be interested in these also. Hopefully you'll get some better answers than this one...
Saw posted about 8 months back someone had attended the API course at http://marakana.com/training/google/maps/google_maps_api.html and I Book-marked the link because they had a list of items they covered in the UX/UI section that seemed pretty straight forward:
* Markers (size/shape/color/anchor/state/quantity)
* Info window (control, overlay, bubble
* Browser compatibility
* Character encoding
* XHTML and VML
* Memory Leaks
Since I don't know anyone who's attended, I've never seen their details, but have used this list as a starting check-point for when I'm doing Google Maps. Always intended on fleshing it out myself, but don't have anything worth showing anyone yet... Anyone have it expanded?