M-ATX taobao browsing, along with some extra 240 stuff.
M99 MATX
28 cm x 27 cm x 12 cm = 9.07L, but requires 1U PSU, CPU cooler height of 65mm, GPU length max 265mm
Honestly quite surprising, they fit that all in 9L
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item.taobao.com
PSU for above
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item.taobao.com
QDIY MATX
390 mm x 170mm x 440mm = 29.17L, no way is it SFF, but interesting acrylic case, though probably sucks for heat management
DENG F15
265 mm x 178 mm x 330 mm = 15.57L, CPU cooler height of 150mm (!), and GPU length of 320mm
I think someone else has mentioned the F12, but this it the big brother. Aesthetically, looks to be the fanciest microwave I've ever seen. It seems it was made only for ITX or DTX, but I muse whether it can fit MATX if the PSU bracket could be rigged to another location.
MJ3
303mm * 188mm * 400mm = 22.79L
Little smaller than the Thermaltake Core G3, CPU cooler height 130mm, GPU length 280mm
SKTC A03
324mm * 161mm * 393mm = 20.5L
I might have mentioned this one before, but gonna post again just in case. MATX is actually 22.3cm x 24.4cm, not the 24.4cm x 24.4cm, but who knows, maybe some modding can do the trick for the latter. I want to hazard a guess that a 360 radiator is possible with this one.
240 rad stuff ___
Jonsbo Sandwich style
169mm x 273mm x 340mm = 15.69L
Jonsbo is now into this form factor. This one supports 240 rad on top, CPU height of 71mm, GPU length of 325mm
Seven-A4 SFX-A4 SL-A4 iTX
315mm x 140mm x 250mm = 11L
CPU height of 50mm, GPU length of 308mm, rather surprisingly small. Seller has few pictures, so will put some buyer review pictures here.
[img=400x400]https://img.alicdn.com/imgextra/i3/0/O1CN01moX6Hv2Gvm0lNbCv1_!!0-rate.jpg[/img]
[img=400x400]https://img.alicdn.com/imgextra/i4/0/O1CN010xpyCt1QwouYWnTMS_!!0-rate.jpg[/img]
[img=400x400]https://img.alicdn.com/imgextra/i2/0/O1CN01ihEy5Z2DzwltipBva_!!0-rate.jpg[/img]