Reddit mentions of Sabrent USB 3.0 4 Bay 2.5” Hard Drive/SSD Docking Station with Fan (DS-4SSD)

What's your definition of "fit"? Do you want to screw drives to actual drive rails/caddies in there, or would doublesided-tape-ing four drives to the side wall of a case work? The latter you could achieve in anything by using a super low power/underclocked CPU, a slightly shorter CPU cooler than the case will allow, then using the space above for the drives. Or you could poke holes in a similarly tiny case and stick your drives on the outside for a different look.

Going in another direction, especially if you need it super portable, what about a laptop and something like this which is a 4x 2.5" USB dock?

What's your actual use case, what is this machine going to be used for?

I thought of that as well. I would like to do that if i can get a two bay enclosure thats small and i can carry it together. I saw this but would like to have it all as one drive but this does not support hardware raid.

https://www.amazon.com/Sabrent-drive-Docking-Station-DS-4SSD/dp/B0711L68MS/ref=sr_1_26?s=pc&ie=UTF8&qid=1526228242&sr=1-26&keywords=hard+drive+enclosure

Every little bit would help. Ultimately it doesn't matter whether you mine with 10x500GB drives or 1x5TB drive (with the exception of scan times/USB bus utilization).

If they are 2.5" drives you could look at something like this to simplify setup, although that's money you could buy Burst/HDD with.

https://www.amazon.com/Sabrent-drive-Docking-Station-DS-4SSD/dp/B0711L68MS/ref=sr_1_fkmr0_3?ie=UTF8&qid=1521481399&sr=8-3-fkmr0&keywords=sabrent+2.5+dock

Here is the bay I was thinking of getting https://www.amazon.com/Sabrent-Drive-Docking-Station-DS-4SSD/dp/B0711L68MS/ref=sr_1_3?keywords=sabrent+usb+3.0+bay+2.5&qid=1571597654&sr=8-3

I've had my eye on this one, sounds like it might be exactly what you're looking for. Small, $50, hot swappable, 4 bay, USB 3.