[Sid Squid]

Sadly, as you say, there's nothing obviously wrong from the pictures you've taken - that's not to say there isn't of course, just that it's not apparent from the pictures.
Head gasket layers can be separated: Normal.
The photo you have which you say shows inconsistency in bore/piston isn't obviously a problem, a better picture might show this more clearly - as discussed earlier in the thread your compression tests suggested neither a problem with bores/rings or head gaskets.
That said a freaky occurance with an oil control ring can't be ruled out I suppose but, even if that accounted for the smoke, as long as the compressions were OK I don't immediately see how that would account for the oil in the airbox; if the oil control were a problem oil might make its way above the rings and into the CC, but that would then go out of the exhaust, only if the crankcase pressure were abnormally high might that account for the oil blown up the breathers into the airbox.

Maybe.

I know I'm not much help - but I think you need to cast your net wider for the problem. Before removing more parts with the consequent costs that involves, a thorough check of everything is definately advised.

I say this cautiously - I'm sure you checked, but are you certain the oil level was correct before the problem became apparent? A high oil level would account for the oil in the airbox, which would also account for the smoky exhaust.