FWIW I think that typeclasses are actually a prime example of what Scala 2's implicits were meant to enable from very early on rather than abuse of them (I know that e.g. the `Ordering` typeclass was at least in Scala 2.9 maybe earlier and context bounds to emulate typeclass syntax were in Scala 2.8).
But I do think your example of typeclasses is a great one. It's a good example of an FP concept (typeclasses thought of as logical constraints to a type variable) desugaring into an OO one (additional implicit arguments).