A leak that was reponsible for a 1.5 quart per 100 miles loss would be very large.
My 240D was using a quart per 300 miles before I rebulit it and there was no noticeable smoke from the drivers seat.... however when I followed the car in a chase vehicle I sould seen blue smoke quite clearly. Have your wife drive your 240D and follow in another car - you may see quite a bit of smoke.
When you did your rebuild did you check the cylinder bores for wear? Most of higher mileage OM61X engines have excessive cylinder bore taper - re-ringing alone will not solve oil consumption problems if your cylinders are not round.