bmw gortex coveralls,like an aerostitch without the import duties
http://showroom.bmw-motorrad.com/Te...MkqlxlEAAAE0tNJtTecS-UXCOM-WFS-en_US-EUR.html
This is what I use and it's very good, straight over my work gear and when I get there I step out of it on the street, give it a shake and stick it in the top box.
I've used it in some serious downpours and it does not leak.