Yeah, those big torpedo shaped propane heaters are really nice. They even have them at Wal-Mart. They'll keep you warm, but you can't hear yourself think while they're running.
I'll try to get to Walmart on my lunch hour today. We need something out there anyway, since Friday comes into the barn in just a couple of weeks. I don't see any evidence of a heat wave coming when she foals (at least not yet, but could happen).