Ask HN: Smallest Computer Case for Holiday Season?

I'm looking to build my father a small form factor (SFF) build for an ITX motherboard with a graphics card of 1050 Ti or greater. I am okay using HDPLEX, Pico PSU, or Flex ATX as the power supply to reduce size. Normally, I would just go to Newegg or PCPartpicker, but I've been seeing unusual cases not covered on those sites. For example, the Geeek A20 Mini-ITX is $40 and has a volume of under 7 liters. I'm looking for advice on what to buy.

I've looked at these: Geeek A30 Mini ITX pre-order. NFC S4 mini is out of stock and it's $200 for the case, a bit much. Logic Supply MC 600 with a volume of 4.2 liters is an option, but I'm thinking, maybe just go for the Geeek A30, since I can use a cheaper PSU and don't need the PCIE cable adapter.

I currently have a 12 core Xeon in a Silverstone SG13 and it is okay, but the SG13 is quite a bit bigger than the other cases.

To be honest, I don't want to spend $200 on the case, maybe under $100 would be better.

The Lian Li PC-Q21B is out of stock and frankly expensive. The dan case is also over $200.

I am thinking of putting a mid-range CPU in there like the new Ryzen 1700, which as a low TDP of 65W. If I use a 1050ti, I should be able to use a Pico PSU 160.

Honestly, every day I look, I see new, smallers. This area is super innovative right now. If anyone has any advice, please let me know.

BTW, I would need to pack this back into a box and then carry it with me on an airplane for the year-end holiday family reunion