Brick, I think it all stems from Shakespeare and his 'Julius Caesar'. Sorry if it offends you, but Russ Crowe or any of the old Brit Shakespearean actors rounding their vowels in a toga or a Roman soldier's short leather kilt somehow works for me where Victor Mature or Robert Young trying to look (and particularly sound) believable in a very short skirt just doesn't.
No offense taken (thick skin firmly in place). Just the thought struck me is all.
And to further your thought, does the above mean that a male British accent does go well in a very short skirt?
(Not that there's anything wrong with that...........)
Re Spartacus - weren't the evil Romans played by British actors while the 'heroes,' Spartacus and his switch-hitting buddy (played by Tony Curtis) Americans?
My favorite miscasting of John Wayne was as Ghengis Khan. Classic!
Re the Vulcan in Brazil - the Shrike made a wonderful coat hangar if I remember the photo correctly.