I think you're right in that the pump probably can't handle the additional block. that tubing is pretty restrictive to begin with, then adding another block on top of it. My pump, block, radiator and res are all on the same level within 1 inch (not incl rad height). My balls still only move a little, about half way to the top. (try typing that without a grin and a giggle) I'm sorry that you have one dead ball.
As far as another system, I'm afraid you're beyond practical exp. from me for pump recomendations., though you may find an elctrical box to fit the dimentions. Don't know about a pump though.