Polar plot an smithchart

Hello,

I'm a happy user of matplotlib. I have both a usage question and a more developer oriented question. First the usage question. I have some trouble using the polarplot. I routinely need to plot complex valued data on a polar grid. But it seems the polar plot requires an extra step where I have to compute the magnitude and phase of my data. Is there an easy way around this?

I would like to develop and contribute a smithchart plot routine but I'm not sure what the best way would be to integrate it into matplotlib.matlab. I understand I would need to create a subclass of Axes for the grid but how is this then integrated into the matlab.axes command? A plotsmithchart command should definately understand complex valued data.
A smithchart grid contains a lot of arcs, looking at how the grid is implemented in PolarAxes it seems there are no circle or arc primitives. Is this correct?

for a brief introduction to the smith chart see:
http://en.wikipedia.org/wiki/Smith_chart

Best regards,
J├Ârgen Stenarson