dh key exchange via ascii email?

[Ileana]

Hello,

I am curious if there is a built-in or optional way to do a
diffie-hellman key exchange over PGP encrypted email.  Such that
subsequent emails could be forward secret?

Is there some program already out there that each party can use to
generate ascii cut and paste primes and factors?  It seems like it
would be a simple program to write.  

Is there any plans to encorporate such functionality in to GNUPG?

Thanks,

Ileana