Belt drives require clever engineering for a clean and painless execution. Chain drive for the win.
Surly Disc Trucker frame - whatever year they made blue ones.
From Surly FAQ page:
You know that serial number on the underside of your bottom bracket? No?! Ok, so flip your bike over and take a look closely at the bottom bracket shell (the cylinder at the bottom of the frame around which your crank rotates). There will be a code stamped into the shell starting with the letter "M". Sometimes this stamp has a bunch of paint that has collected in it but look closely, it is there, I promise. The following number after the M signifies the last digit(s) of the production year of your frame. So, for instance, M2598144 was made in 2002, M8128666 was made in 2008 and M10034269 was made in 2010.