Your machine would only interest to DIY guys because it is not standard PC and no warrenty as a whole PC. Or, it will interest to someone want to buy a 2nd cheaper hand PC. In any case, 2nd hand PC cannot sell much. You can get a local papers to see anything similar there.
Only way to get a decent price is to sell to a friend and you personally guarante it. As all components still got warrenties, it is not too much to guarantee it personally.
Or you can sell it in pieces in ebay (personally do not like it).