I think the Metropolous metroplex is the best plexi clone on the market. The feature set is just so expansive and well thought out and george M knows his stuff when it comes to what a plexi should sound like. Check it out:
Everything but the main rhythm is processed heavy with eventide H9000. The main rhythm is all plexi pushed to death. The head has a built in variac that gets things squishier too. Maybe I’ll shoot up some sound clips.