I worked at Carnegie Mellon University's Field Robotics Center (as a student) in 1991/1992. At that time they were developing a mobile robot called the Tessellator, to service the ceramic tiles on the space shuttle. This was the first application I ever saw of mecanum wheels.
http://www.frc.ri.cmu.edu/projects/t...sellator.shtml
I remained fascinated by the technology, so much so that when I ended up in the Robotics and Remote Inspection group at the Idaho National Engineering Lab, I used mecanum wheels on a miniature drive train I developed for remote inspection in confined spaces.
http://mysite.verizon.net/t.ferrante/MMWV/MMWV.HTM
I designed and built what I believe to be the smallest wheels of this type made until that date, maybe even until now.
Both at CMU and at the INEL, the people who worked with these wheels pronounced it MEK-uh-num.