I'm not sure if something like this is possible (maybe it is?) it would be great to see though.
I'm presently working with a client who has requested a dynamically updatable product catalogue, which I've made 100% with WordPress, mostly with extensive use of custom fields. The one feature the client has requested that I haven't been able to achieve is password protecting certain elements of a page/post (in this case the custom field related to product price). I wonder if it would ever be possible to have a conditional type statement (i.e. if wpUser=="Admin" then display whatever code follows). This would be great with clients like the one I'm working with, who have clients that need to see prices, but end users who shouldn't be.