slideshow / media share application

Looking for an ipad application to do the following: basic video and photo slideshow that loops existing media on an ipad media within application to automatically update / download new media to all devices that have been synced to either dropbox or a folder on our ftp. (dropbox preferably) The latest downloaded folder to become the default slideshow basic use: We have 20 ipads across the country with different retailers. We want our slideshow to run on each ipad. We also want to update the media on the ipads on a monthly basis (as simply as possible for the shop owner) from either an ftp folder or dropbox or whatever. so the device will primarily live offline (meaning the data must be downloaded to the device) then once a month the retailer will be notified there is new content available, they will take the device online and heres the trick - the device will find the new available content and automatically download it to the application. This new folder will become the new default playlist for the slideshow. It doesnt need to look pretty just functional. If theres any more info needed please let me know, otherwise looking fwd to hearing back Cheers, Dave