No sooner is there a rumor that Apple is planning an event (in this case, a March 24 one) than speculation begins on what the company is going to announce during its presentation (presumably a Jobs-less one this time). Already there's talk of fresh versions of Mac desktops, and Engadget is reporting that new versions of Apple's AirPort Extreme router and Time Capsule router/network storage have reached the FCC.
Since both devices already work on either the 2.4GHz or 5GHz channels, Engadget speculates that the new units may work on those frequencies simultaneously. In fact, correspondence on the FCC Web site here and here seems to confirm this. There are no other noteworthy details that can be gleaned from the documentation, such as new capacities for the Time Capsule. As you probably already know, the 5GHz channel is lot less crowded with interference from other devices like cordless phones, which can impact 2.4GHz-based networking. This simultaneously dual-band support is still fairly uncommon among new networking productsno doubt related to cost considerationsbut price has never been a big concern when it comes to Apple's product launches anyway.