Seeing as it is a legal document, I'd suggest checking with a lawyer. I know it's a bit of a cop-out answer, but your best bet for legal advice isn't going to be a forum
Anything I say after this is not legal advice, it's just a personal opinion.
That being said, perhaps your standard contract along with any additional clauses that need to be added after discussion with your client would be the way to go. You'll never create a single document that will make every possible client happy.
I think this is an interesting topic, so I'd be interested to hear what you finally decide to do. And hopefully you'll get some opinions from people who are more experienced with model releases.
And one last thing... Welcome
