Right now this market is (under-)served by some Intel Atom boards.
https://www.solid-run.com/marvell-armada-family/armada-8040-... - $369. You can get it in a case too (https://www.solid-run.com/clearcloud-cloud-iot-core/)
https://www.phoenicselectronics.com will sell you a Gigabyte MT30-GS2 (Cavium ThunderX 32-core) 1U system for around $2k. If you want to provide your own ATX case - much less.
Gigabyte XGene-1 designs based on MP30-AR0 in 1U are literally $1k. http://www.nextwarehouse.com/item/?2465024_g10e
https://www.solid-run.com/marvell-armada-family/armada-8040-... - $369. You can get it in a case too (https://www.solid-run.com/clearcloud-cloud-iot-core/)
https://www.phoenicselectronics.com will sell you a Gigabyte MT30-GS2 (Cavium ThunderX 32-core) 1U system for around $2k. If you want to provide your own ATX case - much less.
Gigabyte XGene-1 designs based on MP30-AR0 in 1U are literally $1k. http://www.nextwarehouse.com/item/?2465024_g10e
https://www.cnx-software.com/2017/09/24/gigabyte-synquacer-9... https://www.socionext.com/cn/pr/sn_pr20170922_01e.pdf
It has 24 low-end 64 bit cores, and up to 64 GB of RAM, dual ethernet, PCIe, ...
It's a bit of an odd board because those cores will be very slow, and I guess they're hoping to make up for it by having lots and lots of them. That didn't (IMHO) work well for the Cavium ThunderX, but I guess it will come down to price (supposedly "under $1000" which is many times more than an RPi, and many times less than an Amberwing).