You need a specialized password storage device which attaches via USB and supports two operations:
- set the password for a given username
- check the password provided for a given username
The device could have some rate limiting to say one check per second for the same username, and 1000 checks per second in total. Surely it could be built using a Raspberry Pi or whatever and then it would just be normal when setting up a server to get one of these devices plugged in and use it for password storage. (To keep the passwords secure even if the device is stolen, it should use pessimized salted hashing for its internal storage, but this is not strictly necessary.)
Of course, many servers these days are virtualized, so Amazon S3 and other cloud providers would need to give you a virtual password-checker attached to your virtual server.