I found out through my rep at Sweetwater that the G10 does indeed have CableTone activated permanently in it's circuitry, cannot turn it off. It is set to replicate a 10' cable. Well, it must be a pretty crappy cable as a model, because I can hear it and don't like it, it muddies up my sound. I wouldn't mind if it just knocked off some highs, but it does something to the midrange I don't like. So I sent it back.
The G10 is such a cool product and I love both the design of it and the performance, with the exception of CableTone. Sure wish Line 6 hadn't done that to an otherwise superb product.
Line6: don't monkey with a man's sound!