mrman3k, I am using the Vantec Nexus multi-function panel with a Vantec Tornado fan. I admit, I think it's odd that both of these products are from Vantec, yet they seem to be so incompatible. What I did was cut the black and red wires going to the 4-pin connector, then put these two wires in the 3-pin connector with the yellow RPM monitor wire. It seems like I had to cut a 3-pin connector off of another fan as the 3-pin that the RPM cable is connected to didn't have the metal wire pins already in it.
Anyway, it seems to work fine most of the time.. For some reason though, sometimes the fan doesn't respond to speed adjustments. The LCD display and USB/FireWire ports work great though. Another thing I didn't like was how easily the screw mounts on the side of the panel stripped out. I guess it does what it is supposed to most of the time, but honestly I'd look at other options.