You may not be able to outright but a pink or purple line, but you can have one nevertheless. Buy a white line and dye it. Snowbee makes a few white lines, and I am not sure, but Trevor Morgan may make a floating single hand line that's white. I own some of his spey lines with white heads. The snowbee link is here;
Trevor Morgan link here;
Trevor Morgan FlyFishing - Exclusive Javelin ® Fly Line
If you need information on how to dye lines just let me know.