I will check in the doc for the guidelines (my addon is already +/- PEP80-compliant, it won't be too difficult to get it fully compatible).
What bothers me is that it currently is in development stage, I would wait a bit and get more feedback from users before asking for trunk-integration.
Speaking of developement, version 1.6 is now available with... custom coloring option! Please try it!
I am currently not very happy about the layout, if you have better ideas about how/where to place widgets, I would be happy to hear them (maybe simply make a proper panel rather than integrating in an existing one?).
Another (small) change is the line width now limited to 10.0. It's actually a limitation of bgl/OpenGL, maybe you had already seen that values in 10.0-20.0 in the UI had no influence on the display.