eBay
SSL sub mixer designed to work in conjunction with the 4000/6000/8000 E or G series music recording console, originally designed to be powered via the mixing console, there is no reason why it can't be powered with it's own PSU - all ins and outs are on EDAC connectors. 
(sorry, I don't have any technical documentation)

Although the listing is "collect in person" if required the unit can be packed ready for collection, freight arrangements however would be the responsibility of the buyer.