The coolest cantilevers that I ever owned were Onza H.O. brakes, you gotta have the Chill Pill hanger to go with it, it's still one of the nicest designs in my opinion.
As far as unique or mind bending... nothing beats the Brovedani ABS Anti-Lock cantilever! Pure delicious madness!!!
Here is a link to a bunch of cable actuated brake treats:
http://www.blackbirdsf.org/brake_obscura/mtb.html
Enjoy!
-D-