I have heard that they make a heated blower for spas, and have been searching and searching for this with no avail. Has anyone used one of these? How does it work, and where do I find one??

I've had both heated and non heated, and quite honestly I didn't notice a great deal of difference. It's intention is to help prevent the air from cooling the water too quickly. A few online retailers carry them, but IMHO I don't think they are worth the extra cost. Consider this, the blower is (usually) located inside the spa cabinet, which is (usually) at or near the same temp as the spa itself. You are essentially drawing in air that is already heated by the spa anyway.