Here's an aftermarket stainless steel lid hinge that can be installed on the 18.5" WSM. I've never had a problem finding somewhere to put my lid when off the cooker, but if you do, this might be for you. Would be interested in hearing from satisfied customers not connected to the seller.
http://unknownbbq.com/custom-wsm-hinge/
http://unknownbbq.com/custom-wsm-hinge/