Draining the battery that quickly should be heating something up, a draw that large would likely melt most wires in a car so I'd be suspicious of larger Components. The main feed for the car that goes through the ammeter I believe is 12 gauge, look under your dash and make sure it's not starting to melt at the gauge.
Going back to your question about the starter, again yes it can draw current sitting if the positive isn't properly insulated. Pull the battery cable off then read ohms from the stud to starter body, if it's shorted you should see it on the ohmmeter.
Sorry I haven't seen your other thread but trust hunt2selk's judgement, if he's saying it's that bad then you better just fix it right and be done with it.