Okay folks, I found the problem if you guys are interested. The modules on these digital radios are designed to unload a signal during use. If you're sitting at your bench right next to your helicopter tweaking it with the radio on and the sticks making little to no movement, the radio is not unloading it's signal, and as such, the module on the back can get pretty toasty over an extended period of time. Extending the antenna does help some, but it will still heat up if you're not giving any sort of input to the radio for it to transmit. Basically, just do your adjustments over a period of time with some breaks in between to avoid cooking your frequency module. This is a problem common to all module based frequency radios, and even applies to some crystal based radios, and is not exclusive to Hitec. If you're using your transmitter with a flight simulator, simply take out the module (or crystal) while you're using it and you won't have any more problems.
I'm sure you've all also noticed that, during use, if you're actually flying your model, the module will only get slightly warm, but never hot.

So, if you're at your bench working on the heli, extend the antenna, and take breaks inbetween to avoid cooking, and you are OK

You'd think Hitec would include valuable information like that in their manual..