"Once I make the connection to smalltalk, wrapping these objects in the (annotate ..) layer seems redundant. Just get rid of types entirely."
So... what... just use duck typing for everything? :P Duck typing is easier, but has a greater possibility for strange bugs and conflicts. But Arc is a LFSP, so that might be a good fit for Arc.
Which, in fact, describes something almost completely identical to my message passing idea, except that it's more verbose in Scheme than in Arc. It even demonstrates prototypical inheritance.
The only difference is that they're using a separate function to represent each method... whereas in my examples, I've basically written the methods "inline" so there's only one function. However, I did demonstrate one way to give each method a separate function: http://arclanguage.org/item?id=14368
