Just for fun: www.athleta.com
They don't have any running rain pants right now (maybe in the fall) but all their pants are belly-button or lower. They have a cute categorizing system for how far below the belly-button their waistbands land (1 finger <index> 2 fingers <peace> 3 fingers <scout> etc.)
Have you tried Lucy of Portland? I think it's just called "Lucy" now. www.lucy.com (i think)
SportHill specializes in running gear. www.sporthill.com And there's always Brooks www.brooksrunning.com
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson