Haha I don't think the Bible is that bad! ^^;; I also don't think it'll go THAT in depth. I think people might get a little bored if it keeps going on and on. I'm sure it'll end once all the character relationships (like Hana and Ango/Ryo, Arashi and Ango/Ryo, Summer A and Kaname etc.) have been settled and people are able to live as a big (or maybe a few) communities. :D

I prefer series that don't go beyond 30 volumes. I think between 20-30 volumes is a good length for a well thought out and planned series. :) Plus, we all know that even if 7 Seeds ends, Tamura-sensei will be able to come up with something equally good, if not better!