I disagree with you (since I've wrote the code in the first place) that it brings another headache to maintainers.
If I want more than one possible color/font schema in my app, I'm faced with the headache anyway. I really don't know how vroom handles this in his code, but somehow he "knows" that you've selected (default) in your user settings Theme container, and applies the default colors. In the same way he could "know" that you like lime green 20 pts Helvetica fonts on a pink background, without hurting performance.
My solution was to let the users get controlled access to some of the settings I was applying anyway, and made them able to set theese as they saw fit.
I do think that colors/fonts is a matter of taste and if you like the original colors, vroom has done a good job.

/brother t0mas