Greetings Ladies and Gentlemen,
I tend to agree with Chuck on the notion that this could be a costly marriage without some kind of stability assurance. My recommendation would be to have Cayenne be standardized so that at least there is both proper documentation and be able to say what Cayenne is intended to be (EOF like or otherwise).
I did some work on the subject whether WO/EOF is still king of the ORMs for my dissertation qualifiers in November of 2011. I found that while there is no notion of a standardized ORM out there, EOF has a de facto standard due to its age and open source varieties in both Objective-C and Java forms. I can see why Apple has been reluctant to take it to a standards body. Namely, why teach the whole industry how to build something that makes your company so successful. None the less, there are enough of us that could easily reverse engineer EOF along with Cayenne to help formalize such a standard with say the Open Grid Forum (OGF).
Of course, there is probably nothing that can be done about the language of choice. According to the TIOBE index, the three most popular languages as far as applications built by them are in order C, Java, and Objective-C. Popularity does not necessarily give us good languages from an academic point of view, but there are some blessings to be had from those top three. Of course, Objective-C did rise this last month to surpass C++, C#, PHP, and Visual Basic. What does Chuck say if people are using those languages, of their own free will?