I got tired of dismantling my Vindicator controllers tonight, and successfully made a top-fire T-stik out of a T-stik Plus base, and a Top-fire Super handle.
The only modification I had to make to the handle was to add a second E-clip, to keep the stick from dropping in too deep.
You could use a spacer to do the same thing, but I didn't want to sacrifice any of my pieces to make one.
For the firing part, I just built a frame below the stick, and mounted a leaf switch on it, for the bottom plate on the firing mechanism to hit.
I'll post some pics tomorrow, showing what I did.
It's all "proof of theory" work, so the fit and finish isn't up to what I'd do on a final version--but it works beautifully.
The one thing that I haven't been able to do yet is get the top-fire to work AND keep the switch from the top though.
I have a few theories on that, that I may play with in the future.