Thanks for all the replies! I certainly don't dismiss the added convenience of the integrated Nav, but between phones, tablets, and handheld GPS units, I'm of mixed mind about it.
My primary intent was to understand how likely I was to find a Sport without Nav at a dealer, or if I was going to have to order one from the factory. I've searched inventory at about 20 dealers now through the Ford site, and I'm not sure I've seen one AWD Sport without Nav!
And as some are reporting that model year '12 production is all allocated, that complicates things a bit and delays timing.
Also, resale is somewhat of a concern - for me primarily whether not having Nav is going to make it harder to sell the vehicle in 3-5 years (or whenever). That's the reason why I was trying to get a handle on whether the majority of people get it or not.