Bit of a long shot I know but how would you feel about this? Personally I'd love to be able to go and see Hibs play against some English/Welsh sides even if they were drawn from the lower divisions. Playing someone like Sheffield Wednesday or Brighton sounds far more interesting then your usual cup trips to Ayr or Raith. Not too sure what the incentive for English sides would be - not too sure your Man Utd's or Liverpools would be too keen on an away trip to Aberdeen on a Wednesday night (no disrpect to the Dandies!) also, could also see the police having major concerns about this. If Hibs drew Millwall or Chelsea got Celtic (infact if almost any English club drew Celtic) there could well be trouble.
This might be the kick up the arse football needs. You can only hope i suppose.
However, if it's midweek games attendances would be low. Imagine like you said celtic drew chelsea, i'm sure the first season the novelty would draw big crowds but as time passes it would just be a trip to london on a weekday that no one can afford or has the time to do.
Taking all these reports with a massive pinch of salt. The way football is going it wouldn't surprise me if a European 'super league' became a reality in the next 20/30 years with smaller clubs playing at a wider level i.e. integration of the football league/spl. Few scottish clubs would hold their own but for most it's be ruinous.