actually this option can be done like how they do multi server for file server. a good idea indeed...

well beside this i would like to suggest that thumb are stored in multiple folder as ftp max file view is around 2400 file? or less (not sure bout that) let say u have 3k videos thats means u have 3k x 4 file in 1 folder. (since vshare did convert it into 4 files which is vid.jpg, 1_vid.jpg, 2_vid.jpg & 3_vid.jpg)