I like Frank Ford's follow rest, and had plans to make one. During the design phase, I realized how fiddly it was going to be - being mounted to the QCTP, you cannot retract the cross-slide (meaning you have to do a reverse-gear pass, which on my threaded spindle lathe is not ideal), and all adjustments when turning down diameters have to be done right there close to the tool-workpiece interface.
I haven't fully rejected the idea yet, but I am considering using a box tool in the 3/4" QCTP boring bar holder instead. Many of the same limitations, and probably much better for threading.