I would also like to request this feature - My use case is a bit different.
I want to be able to use Backup Copy jobs as sources for Surebackup because we use Virtual Labs for Development, Pre-Deployment Testing, Problem/Troubleshooting issues, Testing of patches and other testing scenarios where we want to use like-production systems to test against without affecting the actual production servers. Here's the problem though - We run backups 6 times per day in production. Surebackup for say our exchange vLAB takes about 1:30 to 2 hrs to full startup. Let's say I start up that lab at 11am. Because the lab depends on the backup file it will at 12pm fail and be automatically shut down when the next production backup runs at 12pm. This forces us to do things like temporary backup jobs of the servers in that lab so that they are not locking up the prod. backup files. While this works for me, it is a pain to have to do that AND an unnecessary waste of disk space. It can be a nightmare during periods when developers are asking for test labs for various things left and right. If we were able to use backup copies - I could pick copies from the DR site and have them use those all day long since the hosts, backup files and all the resources there are really not being used most of the day.
The point being SureBackup is not just a tool for testing backups (which you obviously know) - we use it mostly for the lab scenarios so it would be great to give more flexibility in this area with where you can get the servers for the application group like backup copies in addition to what's already offered.