I have been reading that thread, but I'm afraid I have little to contribute to it - I only really have experience of creating small access apps in a trusted environment.
To the extent that security/access restriction has ever been required in any of my database applications, I've handled within the design and coding of my forms and VBA.
For example, at the moment, I'm working on a small app that has all the different functions on tabs in a tab control - some users only need some tabs, so my app starts out with them all set to visible=false, only changing that after the user has logged in and his/her settings have been read from the user table.
This wouldn't be a very secure way to do it, except that the back end resides on a server to which only certain users have access - and this is controlled by Windows Group Policy.