For that matter, unless you want to mount your systems on disks that are permanently in your rack, why not just have your boot files and partitions <plus> the OS on the same disk? In other words install your entire Windows including boot on a removable disk. Install your openSUSE including boot on another removable disk. Swap the disks in and out when changing OS, and since the boot for that particular OS is on the same disk, there is less chance for error and confusion.
You can use any hardware with removable disk bays, extra features are just that… extra.