I Understand your problem had something similar when my one of my 1TB discs got full with movies and tv series.
I dont have a solution for you and i dont really see a problem here though.....or atleast not for me =)
My solution was to separate movies and tv series on separate discs, this works great!
Since you have such an well managed folder setup why dont you just have some genres on one disc and the other genres on another disc?
Soon i will have filled up the movie 1 TB disc and i'm a messy person so i just like to have all movies in one folder, after all its alphabeticly. So i think i just separate the alpabet and have movies A-L on one disc and the rest on another =)
Well that's my few cents on this.
Sry for any typos i just got throbbing headache at the moment =(
Intel Core 2 Quad Q9550 |16 GB Aeneon DDR2-800 CL2.5 RAM | Western Digital VelociRaptor - 300GB 10000rpm 16MB | 4 x Samsung SpinPoint - 1TB 7200rpm 32MB | PS3 with Samsung Spinpoint M6S HM500LI - 500GB 5400rpm 8MB 2.5zoll - SATA300 | Samsung LE 52 A766