After the fuffing and fawing required to get the Wacom tablet up to speed, swapping the buttons on the Kensington trackball required just one stanza in /etc/X11/xorg.conf.
To wit:
Section "InputClass" Identifier "Kensington Trackball" MatchProduct "Kensington Expert Mouse" Option "SendCoreEvents" "True" Option "ButtonMapping" "3 8 1 4 5 6 7 2" EndSection
For some no-doubt logical reason, it Just Works without an InputDevice stanza or anything in ServerLayout.
That will swap the buttons on any matching trackball, should I be so bold as to plug more than one in at a time …
The old FDI file is there.
The Smell of Molten Projects in the Morning 