I am exploring options for a network attached storage system, but I want to have full control over the hardware, so a prepackaged system is not a viable solution.

I also have access to free Intel NUC units, the specific model is something I can pick at the time I decide to get it.

There are super-tiny mini-PCIe RAID controllers like this Syba unit that i can use to connect the drives.

What I can't seem to find is a chassis that can accept a NUC board but has space for two (or even better, three, because the NUC has it's own SATA port) 2.5" or 3.5" drives. Every chassis I've seen only fits one 2.5" drive.