I tried this for my iPad 2 at my local Fedex facility in Fort Worth, and they wouldn't give it to me. It was on the truck, and it hadn't left the facility, but they said that Apple required them to make a delivery attempt even though I was standing right there with my ID and order confirmation and tracking information. They said that once that they'd made the delivery attempt that I could then pick it up that evening at the facility when the truck returned. I was very polite, and the Fedex guy thought that it was a silly requirement, too, but his hands were tied. I'm sure that there are good reasons for this, but it was frustrating.
Anyway, I had left a Fedex signature authorization on my front door, so I rushed home at lunch and got it off of the porch. I don't think that I would do that with a big iMac box sitting on my porch, however.
If you're nearby, you might as well give it a shot, but I don't think that they'll release it if they haven't made at least one delivery attempt.
Thanks for the info. As it turned out, my tracking info suddenly updated to "out for delivery" at 9:48 and "delivered" one minute later at 9:49. I saw it on my phone before our receptionist could even buzz me. I rushed downstairs, and there it was along with the iPad. Nice job FedEx!
Unfortunately, I have an afternoon appointment, so I won't get to use it until late afternoon or early evening. But I'm just glad I have it a day earlier than expected, so I'm not complaining.