My 2012 has not seen many highway cruise speed but for one time touring, at a total of 1400 km, which has a few > 100 mph runs, I did notice a very slight drop in oil level. Was using a low cost fully syn oil, 10W40, Penzzoil Titanium Fastrack. At some point after the tour, I did open up the air box and notice traces of oil.
For most part of my usage on commuting, no loss of oil.
I agree that the oil is not lost via the rings but some gets trapped in the air box while some gets ingested back to the combustion chambers. I do see oily residue in the TB as evidence. I have helped service a friend's S10 that he regularly tries to hit past 200kph and found a lot of oil in the air box.
I believe at high speeds, the crankcase pressure is a lot greater to push out the oil mist to the air box. There is no resistance for the flow between the engine and air box. The air box, at high revs would be in vacuum (lower than atmospheric) and further encourages the pull of the hot gases from the engine.
For car engines, a PCV valve is employed to meter the ventilation. A stucked closed PCV often results in breaking the engine gaskets due to high pressure build up inside the engine. Some employs a oil catch can to prevent the oil from returning back via the TB. There was a case of a S10 with a kinked oil return hose that resulted in blown engine gaskets.
I have also been thinking of designing a 'PCV' device so that the condensated oil can return back the same way it came from but fearing that the pressure build up in the engine may cause more trouble than it's worth. Some ideas are like the distillation process where a long winding path for the gas flow to go through and as it cools along the path, it condensates back into liquid and flows down due to gravity. There is no pressure restriction and would be safe.