Indeed, something like an EMCO F40, which can usually be found on eBay for 55 bucks will do a fine job of providing the HV for the Hallicrafters. Here a F40 (rated at 4kV full load) is producing about 5.6 kV, to a Hallicrafters.
However, the F40 requires 15 volts at around an amp to power it, so that must be fabricated, as well.
EMCO info:
http://www.eie-ic.com/Images/EMCO/EMCO/fseries.pdf
jr