Stephen,

> >> I need to add an instance variable to MethodContext.
[...]
> Yes, I do.  ;)

Yes, I guess you have :) On the other hand ... no perhaps not ;-) Have a
look at the "receiverMap" slot in MContext - it's unused so far and you
*could* hook your forwarder into it. It will break on J3 (which uses
receiverMap for its internal purposes) but my guess is that you probably
won't care at this point. It would at least allow you to do some experiments
with the stuff you're doing.

Cheers,
  - Andreas