What product is Apple launching on May 19?

In anticipation of Apple's 10th Retail Anniversary on May 19, retail staffers have been given strict orders to protect mysterious shipments and display units that have been arriving in Apple stores this week, as told to Boy Genius Report by a "solid Apple source."

Whatever Apple is planning, it's apparently so important that even the staff working overnight shifts have to sign NDAs with Apple, amongst other stipulations from head office published on BGR:

There’s an overnight shift planned for around 10-15 individuals at each Apple Store to work from late Saturday all the way through mid-Sunday.

During the overnight shift, it’s going to be required that employees lock cell phones in the main office. They will also have to sign an NDA with Apple.

There are a wide variety of roles, we’re told, for the overnight shift. This includes all visuals staff, a manager, a business team member, a few Genius team members, one back-of-house employee, and a few generic Apple specialists.

Apple stores have apparently already received hardware to install, and are expecting more hardware to come on Friday or Saturday. All materials that Apple stores have received have been instructed to be under lock and key until after close on Saturday night.

Apple employees will be putting up black curtains at all stores so that people walking outside cannot see inside.

Employees have had to download gigabytes of data from Apple corporate labeled, “training” in a password-protected zipped folder that won’t accessible to managers or anyone else until Saturday afternoon.

Lastly, all Apple retail stores have mandatory meetings on Sunday, May 22nd. Most meeting are scheduled for the morning, but there are evening meetings as well.

Most speculations on this product launch seem to suggest Apple is updating its point-of-sale system to accept e-wallet payments to coincide with the 10th anniversary of opening its first retail stores in California and Virginia, as suggested by AppleInsider and BGR. According to Nick Bilton's blog post on New York Times, a future gen iPhone could have a near-field communication chip (NFC), which would enable mobile payments via the user's iTunes account. Mobile handsets in Asia have already been doubling as e-wallets for years so it is possible for Apple to be bringing the technology to America (well, at least to its brick-and-mortar stores). This possibility certainly fits with the theme of the occasion. But seeing as no current Apple devices are embedded with the NFC chip yet, this rumor seems to be just that -- a rumor.

Apple is clearly up to something so what could it be? Any guesses?

[Source: New York Times Bits Blog via AppleInsider; BoyGeniusReport]