I have used the Hurst Indy truck shifters, and I believe Daytona makes one also. They are intended for newer models, but the main mounting bracket can be modified to work with the older 3 spds. The type of shifter that mounts to the tailshaft housing, like on a Muncie or T10 4spd., are going to require alot more fabrication.
As for coming loose, I have never had that problem, but I did have a case where the one big bolt that holds the shifter to the main mounting bracket wasn't tightened enough, so it went "out of phase". An extra small bolt to keep the shifter mount from rotating on the main bolt took care of the issue.
