These stills have become a bit of an obsession for me and many others recently, so I thought I'd put up a couple of links to some of the proffesionals that build large scale units.
Christian Carls stills
http://www.brewing-distilling.com/index.html
Holstein Stills
http://bavarianbrewerytech.com/distillery_site/pages/home_wf.htm
Cheers.