Patrick-

>1) would you consider it bad form to use (for example) STRTOFILE / FILETOSTR
> to modify the DBC info in a DBF ?

This is an interesting idea. I'd test the heck out of it, but it might just work. You'll need to address it from the DBC side, though, too. IOW, you'd need to add all (and I do mean _all_) the records to the DBC that you need for fields, the table, etc.
>
>3) is there already a utility to do that ? either from Microsoft or
> someone here UT ?

Yeah. Seems like the COPY TO command would work. As in:

COPY TO NewDBF DATABASE NewDBC NAME NewDBFInNewDBC