overriding default color order and linetypes

There is a serious flaw to my approach. It seems that if

    > plot is called with an explicit linetype like 'b-', then
    > ax._get_lines.count is not automatically incremented.

You should never use an underscore variable since the leading
underscore basically indicates this is an internal variable and it
could be removed or changes at any point w/o documentation. If
something changes in the "public" API, it will at least be documented
in the API_CHANGES file.

I think your best approach is to write some helper classes rather than
try and set the matplotlib defaults

  from mycyclers import colorcycler, linecycler

  for data in mydata:
     ax.plot(data, linestyle=linecycler(), color=colorcycler())

where linecycler and colorcycler are generators of some sort. Rhen
you can alter your linecycler and colorcycler to do whatever you want,
make different defaults for color or grayscale, etc...

I'm not opposed to making the default linestyles and colorcycles
configurable, it has come up a few times, but it may be easier and
quicker for you just to code up some custom classes or functions that
have just the behavior you want.