Ideas to use extra space in NAS case?

[_hg_]

I am only using the 2.5" drive slots so there is a lot of extra space in the case. The case is huge! Any ideas of how to put this space to use?

I could get a 4 port SATA card but I don't really need two additional drives.

You could 3D print a tray to put a second SBC in where the larger drives would go, run power out of one of those extra holes, and connect the two SBCs over serial link? With this, you could use PPP to connect the second SBC to the internet.

Anyone else doing something interesting with the extra space?

[zer0sig]

Just wanted to note that the Clusterboard uses Ethernet to connect nodes, with a built-in unmanaged 8-port GBE switch. It might be easier to do the same here, though a peer-to-peer USB link would require less hardware.