I think your best bet would be to go buy a Mr. Buddy. Don't leave it on all night, just heat up the tent, turn it off and go to sleep. Sleeping bags, hat on head, then when you wake up, heat up the tent again for a bit. If you're bringing a gal friend, you can cuddle for heat too
We used the Mr. Buddy when we lost power in the ice storm in our living room. Even though I know it's pretty safe, I still had apprehension using it and opened two windows for flow through air and we have a CO detector. Better safe than sorry (dead).