Riktw designed, and got ITead Studio to produce, a Cortex M3 based Arduino compatible board called Simplecortex. The board uses the LPC1769 microcontroller from NXP:
The Simplecortex is a microcontroller development board that is shield compatible with the Arduino. The Simplecortex has a fast microcontroller, the LPC1769 from NXP. This is a ARM Cortex M3 microcontroller with 512KB flash, 64KB RAM and it runs at 120Mhz. To make sure that the Simplecortex is easy to use we made tutorials for almost every peripheral on the chip and examples to get you started. There are tutorials for simple stuff like IO control up to more advanced tutorials for MicroSD cards. If you have ideas for a new tutorial or made a tutorial yourself, feel free to drop an email or post it in the forum. The Simplecortex also has an onboard debugger. It can also be used to program external devices like a self made PCB for your own project. No more microcontrollers with pre-programmed bootloader needed.
Via the Forum.