Turns out, that's not how he said it. A Microsoft rep confirmed to us that if transcribed correctly, Ballmer's remarks (documented in the recording below) should read, "We've got broad Windows initiatives driving Windows down to the phone. With Windows 8, you'll..." By "Windows," then, he meant the overarching family of software bearing the Windows name, and not Windows 8 specifically. Says Redmond's PR team:
Makes sense to us, seeing as how Windows 8 already makes good use of WP7's Metro UI. Still, we'll be curious to see how Windows 8 influences Windows Phone once Win 8 gets the final seal of approval, likely sometime next year.
"He was making a statement along the lines of what we've already publicly stated around providing a consistent experience across various devices but all carrying the Windows name."
Microsoft Windows 8
Microsoft Windows Phone 8.1
Microsoft Windows Phone 7