Has anyone played with how to maintain an obscurity-based solution in SharePoint 2010? Or is this simply something that one needs to approach differently?
In SharePoint 2007, you can use a combination of audience targeting, form DVWPs, and filters to display fields as editable only to users defined in the column of an item without needing to actually build complex permissions.
For instance, I could have a Contact Information list with a People/Groups column called "Team Member" and an "Edit My Contact Information" page that displays an editable set of fields only where Team Member = [Current User]. That way, an admin could enter the initial information but only the Team Member could edit it later (although I could create an audience-targeted view that only the admin could see as a "back end.") Meanwhile, the default list view is still just a Web part so I can audience target/redirect that. And everyone in the organization can simply have Contribute access to the list.
It's a convenient model for many solutions that don't really require 100% fool proof permissions but where you still want to obscure things. It has proven infinitely useful in cases where someone wants a column that only particular users can see.
When you move this solution to 2010 though, that lovely ribbon toolbar jump up and shouts, "forget those finely-crafted DVWPs and filters - why don't you have a look at this datasheet view button?"