Sweet, a bug in the Intel drivers that's actually useful! That's the same model TV I have (KDF-60WF655, the 60" version!), and though I don't have the affected PC to test with, stands to reason it'd work in my case as well as anyone else with the overscan problem. I know Intel's completely full of crap saying that interlaced modes can't underscan, but the trick was getting the UI to allow it. I never even saw it offer me the underscan options, but I didn't know about that arbitrary limitation at the time so never tried lower resolutions.
Hopefully that info helps out some other people with the same problem - and in a dream world, it'd be nice if that info would be passed along to get this issue fixed at the driver-development level. Hope all our documentation here doesn't just fall on Google's ears, but Intel's as well. Thanks!