Thanks for your suggestions about the radiators, folks, but I'm still stuck. I called Housewerks -- where I plan to go and spend a great deal of money once I have some studio space to work in -- but they don't take radiators unless they're of the interesting variety: decorative, or interestingly shaped, or what have you. Which makes sense, really. I spent some time on the phone with them, and learned that they don't want our windows, either -- hopefully the housebloggers will want them at some point -- but that if we wanted to get rid of our doors they'd probably take them. Of course, we're keeping our doors, because they're cool -- which is, after all, the same reason they'd take them!
So then I called United Iron and Metal, who do take radiators (and don't have a website). But they pay $100 per gross ton, and you have to drop them off. Heavy as they are, and as many as we have, there's no way we've got a ton's worth of them, and for under a hundred bucks there is no freaking way we're moving the bastards again.
So I'm stuck. Alex mentioned that radiators can be worth between $200 and $400, but so far it's looking like we're going to have to call a hauling company to just take them away for free (if that). Maybe I'll post something on Craigslist. Sigh.