My P15 has a floor shifter on the original 3 spd trans, I have no idea what brand it is but it is very basic and pretty worn out, it does work though. It originally had a short (about 12" long) handle on it which wanted to occupy the same space as my right knee, I bent up a length of 1/2" round bar and made a more user friendly handle for it. Here's some pics of it:
Looking up from directly underneath:
Better angle from underneath:
Looking twards front of car:
Handle attachment, it just screws in w/jam nut: