New control needed for Image uploads

We are integrating Rx with a Digital Assets Management System (DAMS) and want to ensure that only image files that are already held in the DAMS can be added to the CMS.

Our initial thoughts are that we could build a Java app that opens a search window that is pre-configured to only look in the DAMS for already existing image files, restricting the search to files flagged as ‘web enabled’ only. The sys_file control would then be replaced by this new Java app control thus preventing users from uploading files directly from their desktop.

Two questions:
[li]Is this a realistic option?
[/li][li]Has anyone done anything similar?

Any advice would be very helpful.