Hey, I was interested in and food done research for the Metallica project ages ago, I think under s different username. Bummer to see there is no prototype yet.
As time has past, though, I have learned a lot, as an entrepreneur and open source developer, including spending four months developing and building opens source cbc machines, and more than a year working with milling machines.
I have been, in consultation with as many others as possible, been advancing a concept for a more practical, doable metal printer. I put a proposal up at here [forums.reprap.org] . It is pretty well thought out, but we need capital.