Homebrew PCBs

Where does one source these, exactly? My quick Google on the topic turned up a lot of interesting links about printing ON aluminum plates, and a pretty interesting bit of kit from Epson for professional printing shops, but no obvious source of supply.

--- In Homebrew_PCBs@yahoogroups.com, brane2 <brankob@...> wrote:
>
> How about using thin aluminuim plates for printing machines ? They come 
> cheap.
> 
> Bonus is that they already come presensitised with photosensitive layer...
>