For the Yubikey owners out there, a while back I wrote a blog post on how to achieve a similar setup using a Yubikey [1]. All it requires is a lanyard to attach the yubikey to.
In any case, the primary idea here was not to prevent stealing the laptop, but to prevent walking away from the laptop without locking it.
Is it possible to register 2 keys, so that any of them is correctly recognised?