I'm using Bartender4 which has a built in keybinding system. Type /kb, mouse over the button you want to bind, and press the button or button mod (shift+button, etc).
This would work with gear sets, just drag the gearset to a bar, bind it, and you could even hide the bar.
If you're missing something to do bindings, I searched on wowinterface and this was one of the first links:
http://www.wowinterface.com/download...oKeybinds.html
Should work the same sort of way, drag the gear set, set a bind, done.