I'm interested in any of your detailed thoughts on this, for slightly selfish reasons.

I hesitate to go off topic here, so let me know if I'm out of line.

I see three options, none quite satisfying:

Have the addressing unit be the word. CELL = 1. Store characters one per word and waste lots of ...

How does REFILL know where to look? So where does REFILL put the stuff?
In my Forth, these kind of things are all done with a small table of vectors. (A class with virtual methods, if you will.) When the input source is changed, the table pointer is changed accordingly. The vectors include REFILL ...

I came up with much of my metacompiler design before I had much of an idea as to how other metacompilers worked
The metacompiler searches the target image dictionary directly, rather than having a separate host wordlist for target names.

I used the same design, for the same reason. The target ...

Assuming that you could port Forth to something like a PDP-8, would CELL return 1?

I have, and yes, it does. I feel that wasting 4 bits per character in a string isn't too bad and that strict adherence to the standard isn't necessary. EDIT: Also, I'm ok with just addressing one field. (A "field ...

I'm very interested.