Here's an interesting new line of cases, especially for me the 22L matx version. It's very open and airflow looks good, but only 145mm cpu cooler support.

http://www.caselabs-store.com/bullet-bh4-matx-case/

Any thoughts on potential as a silent case?

Seemingly it has a good airflow but IMHO it isn't that interesting for a mATX rig: somewhat limited GPU clearance, limited PSU support, limited watercooling support, limited CPU cooler clearance, limited disks support, what do you (generic/royal) have to do with such a box?
IMHO a 22lt volume is (more probably that not) just too small or the 244 x 244 mATX footprint, whatever the intended use.

Nothing much other than just saw the announcement today, casually searching for a somewhat compact silent m-atx case for a new build. Not really impressed with anything on the market.

There is the larger Bullet BH7. I am interested in silent PC test results for this.

http://www.caselabs-store.com/bullet-bh7-atx-case/

Not enough clearance for Seasonic PSU to be face up. They recommend 20 cm but apparently there is only 7mm. But could use a hybrid fan Seasonic PSU face down according to Seasonic, though face up is still preferred.

It is right on the edge for having room for a Nofan CR95C according to their response to my inquiry, but could also use Be Quiet! Dark Rock 3 CPU Cooler.

Also curious whether something like this on interior side panels might have any effect on noise: http://www.quietpcusa.com/AcoustiPack-U ... 439C4.aspx

I was thinking a Intel Xeon E3-1275 v5 in GIGABYTE GA-X170-EXTREME ECC (C236 Chipset), with GTX 1080, Samsung 950 PRO -Series 512GB PCIe NVMe - M.2 Internal SSD 2-Inch MZ-V5P512BW, and maybe a single drive and/or RAID array of WD Red 3TB NAS Hard Disk Drive - 5400 RPM Class SATA 6 Gb/s 64MB Cache 3.5 Inch - WD30EFRX with Noctua NF-A8 PWM, Noctua 120mm, Anti-Stall Knobs Design,SSO2 Bearing PWM Case Cooling Fan NF-S12A PWM fans.

I'm also very interested in this line. With modern GPUs having lower TDPs and shorter PCBs, as well as the shift towards m2/u2 drives, it was only a matter of time before manufacturers statted producing chassis designed around short-throw, direct airflow (there's also the Riotoro 1080, which appears to be a knock-off).

My only concern with the design, in terms of noise, is the overall lack of volume. CL claims that this case cycles out air faster than any other chassis due to the design, but I wonder what fan speeds will be necessary to prevent heat build-up with so little room for components to breathe. I'd love to see SPCR try out one of their gaming builds in one of these.

22 litres isn't the absolute smallest for MicroATX (Silverstone Sugo cases are smaller) so I wouldn't be too bothered about that but where I do have to question it more is the layout - you have a relatively large footprint but with little height. What sort of gap do you have to fill that would make a case of this shape the best solution?

"Gap?"

Also, the BH7 is easily the smallest ATX case available, which is where my concern about volume comes in (multiple GPUs, PCIe SSD + m.2/u.2).

Yes, as in the space on your desk. Specifically wanting something short, yet wide with a surprisingly large footprint. If you specifically want a small volume but can tolerate a large footprint then it is passable, but it's a pretty unusual niche.