Here a basic plugin to display user's location on a map. Coordonates are from user's location field, via mapbox geocoding service (access token needed).
This plugin is not full featured (yet?) but if it can help…

GitHub

Code review welcomed!

@psychobunny You can look at https://www.veloartisanal.fr/map for the moment (until I find how to read and use the restrict access on user details).

@lunar I've uploaded a new version with marker clustering and the fix for chat window.

@davidr As @The-Worms said, go to https://www.mapbox.com/account/access-tokens to request a token

@crazycells i've pushed a new version (0.0.10) yesterday. It should fix your issue, let me know if some problems remains.