Hi
I use a Synology 1812+ which I can expand with 2x 5 drives, making it 18 drives in total, as well as I can add 4tb's instead of 3tb's - you can obviously look at other highend solutions
I think there was something somewhere else where you could pool multiple storage devices into one and the computer would see it as just one location, but it was made up of several different devices - sorry for not being more clear
good luck
Henrik