The worst ones are soldered to the motherboard or built inside the connector bodies, or placed under discrete components.

It really wouldnt be beyond the realms of possibility to modify the bios either.

brokencrow: it still uses PS/2 within a laptop and I think seen as PS/2 is a serial comms protocol that it would be possible to just either attack the "bus" or attach something to the external connector on the inside.

The thing with the device mentioned is that it use a program to download the memory of the device, why is it not possible to poll the keyboard with the data that this program uses, and if it detects a response then you know you have a problem,

i2c