The CDF store has a featured collection of items with Jenkins logos, including stickers, t-shirts, socks, etc.
Cafepress hosts a Jenkins store for various articles with the Jenkins logo on them: t-shirts, mugs, water bottles, etc.
The Jenkins 3D Shop offers 3D printed figures of Mr. Jenkins.
The model for these figures was created by akiki and is licensed as CC-BY-SA.
It can be be downloaded from the logo wiki page.