Building a heater into rear defroster blower hose

i like it.....gonna check into the rx 7 deal and that heater...it looks like that heater has a long resistor in there....similar to what im looking for....ive seen a lot of them but not that one

it needs to fit inside a metal version of this hose that connects the blower to the plastic duct...look at the 6x9 behind it....i have about ½ of that to work with