We actually added support for themes, however we only have 2 options at the moment. The Default or Greyscale.
These styles can get really involved, so we were thinking of implementing preset themes. However that wouldn't necessarily correlate to your specific needs.
What about a way to paste in the JSON code for a custom designed theme? Would that work? You could then use the Google Styler to build the design and generate the code:
mapstyle.withgoogle.com/
Let me know your thoughts.