I have the Hobbico/Tower Deluxe and Deluxe II power panels. No reason you couldn't wire up your own - but I'm guessing the components bought separately would exceed the $20 to buy one made up.
The only two "Tricks" are a switch to reverse the fuel pump (not needed, especially of the pump has its own) and a drop-down resistor and rheostat for the glow driver output w/meter. If you are just using an old plug as a jack to charge a remote driver you don't need a meter or rheostat for the driver.
I added a Voltwatch 12v to mine so I can monitor the lawnmower battery inside as well.