Timbo
10 W
I came across this the other day when I searching for something else. It could a solve a problem for rear suspension frames and also be a flexible add on for anyone wanting an extra rack (up front) when a second batt is needed for longer trips.
http://www.groundeffect.co.nz/product-detail-RCK-ACC.htm
http://www.groundeffect.co.nz/product-detail-RCK-ACC.htm