Gutting my shop

I've wondered about attaching a plenum to the front and running ductwork across the ceiling similar to some of the restaurants around here.
Mine is angled towards the far end of the shop. It actually works really well because the warm air bounces off the far wall and goes back towards the other side of the building. I can raise the temp from near freezing to 70 degrees in 30 minutes.... it's mainly that cold floor that gets me!