I have been using Bruce Guenter's nice Qmail rpms for years, but he doesn't seem to be working on them much.
So, I just fixed a couple of issues:
errno fix (for glibc 2.3)
svc-add smtpd (silly)
So, it now builds out-of-the-box on RH8 and RH9.
I should open a sf.net site for them, probably. Add CRAM-MD5 authentication (I have it working with a plain file, LDAP would be nicer), a working courier RPM (tricky to build sometimes), a little extra stuff (antivirus, spamassassin, autoresponder) and it's really a nice mail server in a box.