I just received my test unit yesterday. The chassis is 19" wide overall. Of course a standard "19 inch" rack is just 17 3/4" wide between the rails, so these servers will not fit in a standard rack - not even close.
The non-standard width isn't a problem for me, since if I like them I'm going to buy the servers and their racks, but any home users should know that these are seriously non-standard.
Interestingly, the unit that I received included rigid plastic airflow shields over each motherboard. This is important for tinkering, since it means that you can run a single server without airflow problems - remember that these chassis are open top and normally rely on having a server above it to serve as the lid.
This chassis is seriously quirky in other ways as well. If you are looking at the images from the auction as reference:
1) You can see a short C-14 female power plug sticking out of the far right side. This is the only power cord you get! It's a custom cable that attaches to the power supply inside of the chassis with an odd connector and is routed out the back of the server where it dangles as a C-14 plug. If you pull on that C-14, it will slide out up to about 16". If you need more cable than that then get out your tools.
2) The disks mount in the space to the right that looks like it would contain the power supply. The two 3.5" disks mount with included tool-free sleds that are shockingly minimal, but do include a small amount of rubber dampening.
3) The small cables dangling out the back of the chassis are in fact the disk cables. The disks mount with their connectors sticking out the back of the chassis, and the cables just plug right in. No backplane, no strain relief, no nothing.
4) The 10Gbe mezzanine board is SFP format, not Base-T, and does not include any strain relief. It is very very wiggly.
5) There are plugs on the motherboard for a second disk for each motherboard, but you'll need to wire your own special cables, and you'll need to fabricate some sort of mounting bracket for the drive itself, which better be an SSD for weight and vibration reasons.