When I first joined Topia, Luscious was supposed to be a finished website and on top of that we still needed to build a client room which they could privately interact with their clients. After finishing the website with way too many rounds of changes, I knew we needed to do the client room right. So I met with Luscious to work out exactly what they wanted from a client room and wrote a specification that we could both agree on. The specificaton was signed off and I began to work on the build, the end result was a website that was both in our minds eye and everybody was happy.
The client room features cascading permissions allowing fine grained control on what clients could do (read, upload, download, preview, mark favourites) etc from a top level folder right down to individual files.