Very interesting project and one that seems to fill the needs of people without the skills or equipment to assemble their own images.
How are you going to handle license compliance?
You're definitely distributing binaries that fall under a number of different licenses and simply distributing the binary doesn't meet the terms of most of the licenses under which the code falls. It's not just GPL, but BSD-style, Apache, Eclipse, and all of them that need to be complied with.