r-studio should see the drives as a raw disk even as they are not mounted by the OS. Last time I tried copyr, it could only access drives that were mounted by the OS, however, maybe they have added this functionality.
A good hardware device for hot swap SCSI is the tableau T4. You need an adapter to go from 80 pin with power (hot swap) to 68 pin. The box then mounts the drive as a raw disk over USB. It's around $400 but well worth it. Also has optional read only settings.
http://www.tableau.com/index.php?pageid ... s&model=T4
Once you can pull the images with R-studio, try rebuild virtual RAID 5 and copy one of the existing images to take the place of the missing disks. It works, you just need to know the type of controller used so you can setup the right block settings. good luck