A quick fix:
In SkyrimPrefs.ini:
fShadowBiasScale=4.0000
Make the shadows kind of pixelly-edged if you look close, but it gets rid of the stripes, at least.
Cheers for this--I'll have to give it a shot and see how it looks. I can live with pixel edges, but the striping was threatening to drive me insane. The screenshot I posted doesn't really do it justice...most angles look like the screenshot BounceDK posted. Talk about your immersion breakers.

Seriously, as f-ed up as the shadows already were, what possessed Bethesda to put in more? And on top of that, not giving us a way to shut them off?
I don't know. Honestly, I do appreciate that Bethesda's taken the time to add in such improvements, and for free, to boot. But I really, really wish they'd also thought to throw in an off-switch.