I saw a cd5 diy where the guy made a short shifter.
All he did was, when you take off the knob, its a metal square peice which comes up.
So he cut the thing in half or less, put a manual gear knob on with a "press down" button, so it does the exact same thing as stock.
the stock one has a kind of triangle on it, which when you put the button in pushes down the metal rod.
Anyways just thought id give my input, will try to find a link, looked very good though, it isnt backwards compatible though