re: Bud Toaster ... this is the smallest battery powered vaporizer heater (computer controlled) that i have been able to come up with:
2 batteries are in an external power pack, connected with 36" cable.
i put it in a 2" cube, but the enclosure could be virtually anything. The oven tube in the photo is 1.5" long, 15mm outside diameter. Circuit card is 1.72" diameter.