My bag got stolen off my bike a few months ago and I haven't been able to find another. It was made by a company called wraptor or maybe that was the name of the raincover.It is very small and lite weight but does a great job of keeping the seat and main part of the bike dry. Shaped like a kite,bungee at the back,bungee on each side and velcros to the handlebar,folds into a bag about six by eight and an inch thick.

 

Looks kinda like a Geza cover: http://www.gezagear.com/