I'm going to proceed with this answer as if you are serious, although much of what you said leads me to believe you are yanking much chain here...particularly the last part about the black liquid.
Your chrystal ball here is going to be your spark plugs. If indeed you are leaking oil, and you're not seeing a leak externally, that means your piston rings are bad and oil is slipping right by them on the intake stroke, into the combustion chamber, partially burning (and gunking up the spark plug), and coming out the exhaust valve (which will be gunky), through the catalytic (which will be soaked and useless), past the 2nd O2 sensor (which will have gone bad and thrown codes at the ECU) and out the tail pipe where it makes that puddle you talked about.
The easiest of all these things to check is the spark plugs. Now that you've driven on your new ones for a while (assuming you don't still have the old ones) pull them and take a look. If you're buring as much oil as you say they will be covered in thick black slime.
As for a "rebuild" - if there's oil in the spark plugs then you do need some degree of a rebuild. It will consist of pulling the head, pulling the pistons, seating some new rings, maybe honing the cylinder walls if the old rings did damage, and reassembling with a new head gasket. Some models (you didn't say what car you had) have a reusable head gasket but a new one is never a bad idea.
I can't believe any reputable shop would do all the work on your car that you mentioned and not tell you that you obviously have a ring problem, but that's really what it sounds like.
The other thing I would say because I've had this happen myself, is to change the oil pan drain plug bolt and washer. With time those can leak. But if your oil pan is clean and dry with no signs of drips then that's not the problem.
While you are waiting for the rebuild some things that help are to clean the air filter, replace the PCV valve, clean the throttle body, and make sure your intake valve train is seated correctly. Check timing too. All of this contributes to facilitating airflow into the chamber on the intake stroke and reduces the chance that vacuum in the chamber will pull oil up from the crankcase instead of pulling air in from the intake tract.
Good luck my friend....for your sake I hope you were kidding.