I do see where you’ve decided to go in another direction, but just in case you circle back around to the D2700 or similar… At the price they have listed and for what I’ve compared pricing on for other refurbished same brand / model units, that chassis may not come with the drive trays (that’s normal), power supplies, fan modules, or I/O modules. Basically just an empty shell. I don’t see the info on the page as to what’s included outside of disks not being and the photos look very stock. Best to confirm what’s really included.
The LFF units hold 12 ea. 3.5" drives which where I’m located are a lower cost, when they’re in stock. Also, and this one I’d have to check the docs on again, more LFF enclosures can be daisy chained to each other than SFF enclosures. I think that’s mainly due to the number of disks so it basically evens out space-wise, but cost-wise may likely be different.
As @matthewjbauer kindly provided, cables and Array Controller would also be needed to go into a host (server / workstation) that could access / share the storage. Oh, and those cable types do vary depending on the controller and chassis.
One last thought; with as much effort as it takes to plot, I’ve gone down the path of setting up a RAID array. The last thing I want to happen after I get all these completed is to lose a drive and have to start a large number of plots over again. Each to their own risk tolerance level of course.