PS – I notice too that when I DO enable a post type to be hierarchical and enable page-attributes, I'm only able to select from the same post type when choosing a parent. Is there no way to make a custom post type (or all of a custom post type) a child of a page?
All in all, this issue comes up on pretty much every site we build with Types & Views, and we usually just end up having to write some custom CSS on a per-post type or page basis that "fakes" the parent/ancestor page status. It would be AMAZING if a non-hacky solution were available.