In further evidence that updates to the AirPort Extreme and Time Capsule are due any day now, Engadget reports that FCC filings for the next-gen AirPort Extreme have surfaced, while 9to5 Mac has received part number info on both the AirPort Extreme and two models of Time Capsule.
Supposedly prices will drop across both AirPort devices, and the Time Capsule will come with two choices in capacity for its built-in drive, either 2 TB or 3 TB. Supplies for the Time Capsule in particular have been constrained in physical stores for a few weeks, and shipping times for the device have slipped in many of Apple's online stores, too. References to both devices cropped up in a recent AirPort Utility software update, so all signs definitely point to a product refresh soon.
Engadget notes that Apple typically likes to debut new hardware on the store on Tuesdays; while we can confirm that's traditionally the case, more minor bits of accessory-type hardware occasionally crop up on other days instead. The next time the Apple Store goes down (if it actually goes down at all), don't be surprised if there's a bunch of new AirPort hardware waiting for you when it comes back up.