You can grab a refurb optiplex 7050 sff i5 6500 16gb box and dual 10g nic for about $300.
They arent as small as the tiny version, but about 11 inches by 3.5 inches, and room for a couple of pcie nics
https://www.amazon.com/Dell-Optiplex-i5-6500-2666MHz-Professional/dp/B08FCTTF95/