I've seen requests for this kind of circuit on a couple of non-Airstream forums. It's one way to dim a bunch of high power LED's using one central control. I used it to make a bright main light fixture for our Airstream.
I took three endor stars and three buck pucks (see previous posts) and bought a 5K linear taper potentiometer at radio shack.
An LM350 voltage regulator was used to provide the control voltage for the three bulk pucks. This circuit could be used for any number of buck pucks connected in parallel.
In this diagram, black is ground or common, red is the
12 volt power,
and green is the control voltage.