rewriting the Host header, switching protocols

Hello, thanks for publishing privoxy. There are two strange scenarios
that have cropped up (don't ask why)

1.  To rewrite the Host: header of a forwarded request to a target
webserver (based on certain criteria)

2. To switch the protocol from HTTPS to HTTP when forwarding a request
to another proxy (typically local, again based on certain criteria)

I understand both of these are anathema to security concerns.  The
first question is are these possible within privoxy or does the
architecture of privoxy prevent one or the other from being
implemented. If feasible I'd appreciate a pointer to the sources where
these could be implemented (I haven't looked at or understood the code
enough yet)