Another vendor offering anti-interdiction delivery of a tamper evident system is Nitrokey. They offer rebuilt Thinkpad x230’s (they call their product NitroPad), running your choice of Ubuntu, or Qubes, using Coreboot, Heads, and a Nitrokey. Deactivated Intel ME, of course.
Nitrokey is a German company, and the Nitropads are built in and shipped from Germany.
The keyboards are quite good, there are hardware kill switches, etc.
With Purism, you get brand new everything. Nitropads are rebuilt, but solid, machines.
The anti-interdiction services of the two are essentially the same.