What options are there for mapping relationships in Models/Entities

My module (the second of your links) supports all relationship types, just some of the entity functions are specific to Many To Many.

What else would you like to see as far as docs?

Ah, good to know! I'll definitely try it out.   As for the docs, I'd like to see examples illustrating the various types of relationships, handling bi directional relationships, etc, as this is what I sort of came in looking for.  The docs sort of have this now but IMHO it seems a bit terse and not real obvious what all the library does.  I'm still not real clear on how the schema module fits in to the picture.  An example illustrating this would be helpful.