whoever told you about me was probably right, the only two i've ever seen are the ones i own, and i've only heard about but never seen two others, one of which is in pieces right now according to the owner...
they are getting to be exceedingly rare, and hard to find, if you can get your hands on one, snatch it!
they work using just the basic autococker components (except the ram) strapped onto a custom front block and slider frame
the 3-way is in the same spot, the reg is moved to the opposite side, the ram is in the same spot and they use a clippard ram with a flow limiter (that adjusts the reactivity) that has a longer throw than a normal cocker ram, i believe like 1.5" or 1.75" instead of the normal 1". below the ram and in place of where the reg would be there is a 2-way switch and a on/off switch. the on/off controlls whether airflow is going to the piston in the grip frame, the 2-way switch which works off the same air as the reg moves air to the piston in the grip and pushes the trigger plate forward. the gun can be either semi or reactive because of the on/off...when it's switched to off, it just closes off all air flow to the grip piston, very simple...the 2-way is opened and closed by the moving of a slotted arm thats attached to the 2-way and moved by a small plastic piece thats screwed into the pump rod...
other than all the wierd operation it's timed and operates like any normal autococker. youc an find pictures of mine on my website at http://www.FirePro84.com/Cown.html
if you need to know anything else feel free to ask, i'm glad to help :-D