I really don't understand why if people want their work in a POD book they don't do their own. Its not that difficult and only requires the will to do it. It can take as long they want and can be organised exactly how they want.
If someone wants to do a community book then it should be 100% up to them how they do it and what the terms are.
If people were sensible they would limit it and maybe say I'm going to do a B+W Landscapes only book. Someone else could do a Colour Abstracts only book and someone could do a nudes book if thats their thing, etc etc. There doesn't need to be only ONE book.
This way you will remove most if not all of the arguments so that it only takes one person with a specific interest in one area to set the rules for the book they want to do and just do it.
If anyone whines they've been excluded then tell them to get off their arse and do a book for their own particular genre.
Is it really so difficult?