Hi Jeremy
I will try to answer your questions:
Icybox make a cloning box, with this you would remove one of your MD600 disks and put it and a backup disk of identical size into the cloning box and without connecting to a pc you simply press the clone button on the front, it will then make an exact copy of your MD600 disk, some Sooloos users prefer this method of backup to running Sooloos backups as it copies your library as it is at that time so gets around the deleted albums still being in your backup issue I discussed before. IP is Intellectual Property namely Sooloos software which resides on the disk as is the case with am MC200 this is not the case with an MD600.
Selecting files via folders is not an option available in Sooloos or indeed Roon, you can store files in separate folders in Roon as I indeed do but Roon does not allow browsing by folders, I think if you embrace the Sooloos and Roon way of using tags and focus you will not miss being able to browse by folders.
Sooloos development: Meridian promised exciting times ahead for Sooloos when the Roon team split from Meridian, I am not sure if you are aware of the circumstances but essentially the original Sooloos team split from Meridian and formed Roon, Sooloos developments and communication from Meridian since the split have been thin on the ground compared to the rapid development and detailed communication from the Roon team via their forum, but as I said earlier if Sooloos does what you want then why change?
Russ