Got this email from Randy, responding to my note to him about wanting to put a 28mm on the back wheel of the XStream......
 
<<As a last minute change on the production bikes, I am thinking of setting up the rear wheel with more clearance and possibly going to canti-lever brakes in the back, keeping the road in front. This would offer better stopping power, and I can increase wheel clearance to go up to 1.5 x26, and use both 650 and 26" wheels. A swap out of the fork and you could do a dual 26 version for the tourist.>>  
 
I reponded that I thought this was an excellent combination of ideas.

It's probably worth giving up on Production S/N # 00001 for the tire/wheel/brake mod.   But I reminded Randy that "Sometimes you have to shoot the engineer and get on with production..."