One thing you could try is using a reverse proxy like I describe in the following post:
viewtopic.php?p=98960#p98960Like I mention in that post, you can then do some (or a lot of, if you know what you're doing) custom authentication logic.
For instance, you could have certain URIs/paths be allowed for only some users, but not all. Or you could do something similar to what I'm doing, and allow any device on the local network (ie wifi) to access a "generic" page, but only allow authenticated (or pre-defined IPs) devices to access other pages or "master" control pages, etc...
Just an idea for those of you that are really wanting multi-user & custom auth schemes -- it is doable w/ this method and really isn't that difficult once you get it setup.