Negotiate. It's always an option in my experience. (For example, I've negotiated the text of offer letter and IP/confidentiality agreements at most of my employers).
And here's something to back you up: http://www.reddit.com/r/TwoXChromosomes/comments/hvv2m/i_wor...
I've only had the chance to do this once, with pretty small potatoes stuff, but damn if it wasn't absolutely delightful.