Hi Dave,
I think that being 110 VAC powered is a not much of a disadvantage for most RVers. When you think about how much time you spend camping in sub-freezing weather, most will find that this time is spent "with" shore power and therefore access to AC power for the pads.
For the boondocker, certainly, having 12 VDC heating pads is what you will want. But you'll need a battery bank that has the oomph to get the job done. Heating elements of most kinds are usually big current draws.
We're trying to gain access to the specs on the heating pads used on the products and when we have it, we'll post it up and we'll all be the wiser (voltage, thermostats etc.).
Thanks,
Jim