Adding a header

Is it currently possible or will it be possible in a futre release to be able 
to add a header to the mail message ifile is scanning?

I use Kmail as my e-mail client and another Bayesian filtering project, no 
names, allows messages to be put into stdin and output on stdout and adds a 
header that the client then can filter on.

I did see that Martin Macok's scripts do this but would like this to be come 
part of the distribution since it would allow an easily portable solution for 
other clients.
-- 
Dave Dulek