Hi!
I have built a bunch of high power LED lighting based on the arduino before (http://saikoled.com).
I am considering implementing a much simpler version of what I have before by taking the arduino leonardo as a base, adding an ultra-bright RGB+white LED (700mA per channel) along with appropriate power control hardware, connecting the now-free USART up to a DMX input, adding on a custom-extruded aluminum extrusion for heat sinking, requiring a 5V power supply (can't run off of USB alone, too much current requirement), and basically creating a fully featured arduino with a very bright LED on it (~425 lumens of total output) that can easily be configured as a DMX LED light.
I'm quite confident that this is feasible, but I am wondering if anyone else has already implemented something like this, or if it is worth my energy to build. I think I could build the system for under $50 each in large quantities, maybe twice that in small quantities. Does anyone think that there would be interest in such a device, or should this be implemented as a shield instead? I prefer making it a standalone arduino to decrease the total cost, but it does slightly decrease portability between different arduino models.