Hi, and thank you for your reply! The steamer is arriving Tuesday. It's pretty high-powered. Most of the attachments do require a cloth, as you mentioned. The steam actually circulates, pulling dirt back through the cloth, trapping it with the heat (akin to setting a stain in a shirt in a clothes dryer).
A lot of steamers do just blast steam, and it's necessary to wipe behind it. In fact, I have a handheld steamer I use at home, just this way. It's a Shark. It's great for dissolving dirt and soap residue, but it doesn't pick it up.
I also have a new extractor on the way. I believe that between the two machines, my detailing time will be cut dramatically, and I can focus on more marketing. I don't mind cleaning interiors, but the real money (and fun, for me) is in exterior work. I enjoy the process of polishing, glazing and buffing finishes.