Switchcraft's line of Micro-Con-X (Conxall) IP67-spec waterproof connectors may be just what you need:
http://www.mouser.com/search/Refine.aspx?Ntt=Switchcraft%20CONXALL%20Micro-Con-X%20Connectors
You want the 3SG type for the cable end (coming from the bike, which carries power) and the 3PG type for the accessory end. The latter can be had in bulkhead mount or cable-end versions.
I used a pair for brake/taillight power feed into a Givi V46L trunk that's mounted to my Concours 14. Admore Lighting also uses them as OEM for their accessory lighting systems.