It's funny, but I recently did something kind of similar ... sort of a "poor boys' " version.
A house, converted to apartments, had just been completely remodeled. However, they failed to reconnect the baseboard heaters. I needed to run MC through about 8 ft. of joists thet were enclosed (above the bathroom), from the outside of the building, without tearing the bath apart.
My solution was to use a large "bell bit" (sized for 1/2" EMT) with multiple extensions. To keep the bit running true, I sleeved the bit in a piece of EMT; the back of the drill head rested against the end of the EMT. Drill joist, advance pipe, drill joist, etc. The MC pull was quite easy.
