Wasn't it the Velocette that you could follow home an hour later by following the trail...? Always used to say you know Velo's out of oil when it stoppped dribbling out. I'd still love a Venom or Viper - I remember the wonderful sound that even the MAC models made.
I'm told that the "retro" Triumph models are leaktight because they have horizontally split crankcases. Maybe that's true of them when they leave the factory, but I never had leaks from a vertically split casing - you had to grind them on glass or a surface plate, though. The only bits I couldn't get to seal were the pushrod tubes. Always carried a cloth and wiped them whilst still hot and then rubbed over the outer aluminium casings as it helped to stop them tarnishing.
I must be going over the hill - I get urges to buy a T100S (short legs) even when the sun isn't shining...
Rob.