I found a solution for my need.
Installed AjaXplorer to a site on the box then configured each chrooted SSH user within AjaXplorer directing their access to where the backup files are stored on the file system. Works beautifully.
Based on this experience I wanted to recommend that AjaXplorer be included maybe as an add-on or somehow with ISPConfig. It works great!
Hope this helps anyone else looking to achieve the same or similar goals I had.