Got word late yesterday that they traced it to a bad gasket on the oil cap. Further searching revealed it's happened to more than a few others out there. What still doesn't make sense is how all that oil could have come out after we parked. (Unless it was sprayed around under pressure while driving and gravity did the rest once parked?)
Dealer has replaced the cap, steam cleaned the engine bay and re-detailed the exterior. They will put it on a single car carrier back to me Monday and retrieve the 550 loaner.
Genuinely bummed to have missed the entire long weekend and will now blow most of a Monday off that was to have been spent getting acquainted and tackling the mod list. But I realize it's a small price to pay in the long run. Post-mod photos to follow.
OE build was MR/black cloth with DCT, Comp, Performance steering wheel, CF splitters, carbon leather trim. Spousal concession for her once a month drive was NAV, which, in a bit of irony, helped the flatbed truck find me on Friday when the car dumped it's oil.