Δαφνη Ευτυχια Αρθουρος

In the "duh!" department, it suddenly occurred to me to wonder if you could scare up a bag of soapstone chunks or dried stone-gravel from some of the folks you know locally. You could get in the habit of putting that on top of the hot water heater or a handy radiator, and then toss it into bed under the covers a half hour or so before you go to bed. You might be able to get jonsinger to run some rocks through one of his shaggier kilns to make sure they are sufficiently dried out that they could never explode when heated, though you're not really going to heat them that hot.

With all the SCAdian and Faire folk you know, I bet somebody out there has sources on traditional bedwarmer technology other than barmaids or pans of hot coals. :-)