At Maker Faire NYC this weekend, Arduino's Massimo Banzi announced that the long-awaited ARM-based Arduino, called the DUE, would be out in November.
The Due is roughly the size of the Mega 2560, but swaps the 16MHz, 8-bit processor found in your standard issue Arduino for a 96MHz Cortex-M3 [Corection: it's 84MHz by default but can be overclocked to 96]. Predictably, the Due is a much more capable development platform, and could easily replace multiple AVR-based Arduinos in products like DIY Drones' UAVs. The Due isn't expected ship till at least November in large quantities, but preview boards are currently being handed out to select developers.
I was there and spent a lot of time with the Arduino team discussing the latest details, including debugger and USB interfaces. We've been working with them for a year on this, and some of the APM team helped with the Due software. Right now the APM team is focused on the PX4 board and bringing ArduCopter and ArduPlane to that ASAP, but that ARM-based and RTOS-based code will also be the foundation of a future Due-based APM board.
Given the delays in Due, we're going to wait until it's out and the community can spend some time with it before pushing out a new APM board; the transition to ARM is not trivial for Arduino, and we've already got a great ARM platform with PX4. But we are working closely with the Arduino team and are committed to Arduino as one of our platforms for the future. It's less about the hardware power and more about the ease-of-use of the programming toolchain and the inclusivity of the community, and Arduino has served us very well on that.
A full video of the Arduino/AVR presentation at Maker Faire is here:
Here are the technical specs, from this PDF: