cubic chunks is out (kinda, its in alpha) underground biomes was one of the things i was wanting to help work on but seeing as quark already has that.. i was thinking that someone could add a check for what type of world it is and if cc is on it.
if so, generate large caves, and the undergound biomes below 0'
if i think of any more things that cc could do with quark ill just comment below or edit

Not interested in doing this.

Aww okay...
Maybe one day when cc is huge?