I really like the goal of usability this is aiming for. Using just `method_missing` by itself can have some interesting ramifications.

Have you thought about providing a corresponding `respond_to?` method?

Something like this might do the trick:

``` ruby
def respond_to?(meth, include_private = false)
  if has_key?(meth)
    true
  else
    super
  end
end
```