All support for IPv6 capable eggdrops is curently own in the 1.3 series and in the much far away 1.7 (devel version number, likely to be 1.8 and maybe above).
I volunteered to be a Dmoz (Open Source directory listeings, that power google) on the eggdrop category, and found a nice little link awaiting my approval.
http://eggnet.warpzone.org/
I am not sure if the code, or patches work, but they are there for all those that wish to try it.
Note: I havn't looked at the code, nor do I intend to, as I have no need. There is a risk of backdoors in the code, but what the hell, it's there to try.