Apple already has a Verizon compatible iPhone. It’s not that
they have to rush around Apple HQ and start building the thing for
a January launch with Verizon — it’s already there and being
perfected all the time. As Gruber pointed out, think of this like
the Mac OS X Intel version. People were shocked when they learned
that Apple had parallel builds of OS X for Intel and IBM, but they
had them for years.