Hi station, hi jfrancho,
apart from a Canon-gearhead I am also an ICT professional
AFAIK the maximum lenght you can cover without (serious) signal loss with USB2.0 cable is 5 meter.
To connect a beamer to a portable (for remote mouse steering) we sometimes extend to seven meters, but the result *is* visible (sloppy mouse movement, less responsive to clicks), so IMHO you would *not* want to have that when connecting a camera
:P :P
...and then the 10D isn't even USB2.0 IIRC, ...so *I* would stay on the save side and not go farther than 3, maybe 4 meter...
PS: as with *everything*, quality (of the cable and connectors) *does* matter, and better 1 long cord than 1 + extension...
...hope this helps some, *my* €0.02 worth...
My kindest regards!
Max@Home