I have been told, that radiant heat in the floor is the way to go. But unless you are building a new shop, it would be quite costly to replace the floor. I know overhead radiant (tube type) works well, although it requires a high ceiling. I would think that the pellet stove idea would be worth pursuing. The only real downfall I imagine wood be the floor space it may require. I would think that they get as hot as a wood stove, so you would probably need to keep anything that will burn away (like your wall). Although, I do remember seeing wood stoves with some kind of shield on the wall behind.
