Using gsettings or dconf-editor, one may set 12 general purpose keys to arbitrary commands in Ubuntu Mate 14 (in the schema org.mate.Marco.global-keybindings, keys run-command-1 through run-command-12). I see no other way to add custom key bindings, and so it appears there is a limit of 12 custom key bindings.
My question: Is there any way to get more than 12 custom keybindings?
I could get 144 options by using scripts to respond to sequences of 2 custom keybindings. However, I am hoping for something that only requires hitting one (modified) key.