It's possible to define a custom tile layer with Google Maps plugin (version => 2.16):

{mosmap tilelayer='http://tech.reumer.net/images/stories/tiles'|
tileminzoom='6'|tilemaxzoom='9'|tileopacity='0.85'|
tilebounds='51.0001625721, 3.0, 54.0, 8.00049916174'|
zoom='6'|centerlat='52.5'|centerlon='5.5'|tilemethod='maptiler'}

You have the following parameters available:

• tilelayer - The url to the base directory of the tiles. Don't add a / at the end.
• tileminzoom - The minimum zoom of the tiles
• tilemaxzoom - The maximum zoom of the tiles
• tileopacity - The opacity of the custom tiles (1 is not transparent, 0 is invisible, 0.5 midway)
• tilebounds - The bounds of a the custom tiles consists of coordinates for leftbottom (southwest) and right top (northeast). All values should be seperated by comma
• tilemethod - The method to get the tiles. This can be maptiler for a special function. Or the complete url and define the x, y and z as parameters in the url like: http://www.yourdomain.com?z=[Z]&x=[X]&y=[Y]. See: Tilecoordinates

If you have problems with maptiler, please goto: http://groups.google.com/group/maptiler/topics