I'm also convinced the poncho is the way to go! I'm glad the OP is trying this time-tested idea! I commute in wet weather with a bike-specific poncho, and I think it's the best solution for me when it comes to breathability vs waterproofness. The only thing that separates a regular poncho from a bike poncho is that there is a waist belt to keep the back from flapping upwards, and hand "stirrups" to keep the front from flapping upward. Add fenders with low mud flaps, and occasionally gaiters, and I can ride in the rain while staying dry from both rain from above and sweat from within. I got my poncho from Center for Appropriate Transport Ultrex Rain Cape » Center for Appropriate Transport