Have you considered using the new cms VIST by Mansion Productions?
It was written exactly to be a backend for online video stores, and can do all of the required things here - tour v/s members area, preview trailers, video scenes organized into full DVDs with covers, synopsis, cast list, groupings by model, director, production studio, keywords etc.
The only thing it won't do for you out of the box is video codecs transcoding, but if this is a dealbreaker, (and if you have a mighty server) we may add-in such module as a custom-made solution.
Check out
http://www.mansionproductions.com/vist/ and contact me at ross [at] mansionproductions com if you are interested. I can show you more.