PLD people have made quite a nice ipv6 patch which appears to work without problems
(unable to test server, but as xinetd can't handle other than ipv4 anyway, I don't think this
will cause any problems..).
The patch is attached. In addition autoconf/autoheader is needed. For a .src.rpm, check out
Created attachment 22928 [details]
rsync ipv6 patch
Oops, this was added in 2.4.6-4 a few weeks back.