Encrypt the hard drive. Insure against theft. Forget about it if it's stolen.
Right, your data integrity is almost always worth more than the hardware itself. In order to install a tracker, you have to permit the attacker access to your filesystem. Don't do that.
If my laptop is stolen, they'll see a grub screen, and then dracut asking them for a password. I'm SoL on ever seeing it again but I don't have to go explain to clients how their security may have been compromised.
I guess ... you could try to bait them with a Windows boot option in grub. Maybe even make it the default if you think it's really likely that your laptop will be stolen. Install the tracker there, perhaps. One could continue along that train of thought with silent grub options and delays to make a deadman's switch of sorts, that would automatically bring up wireless, connect to any routable AP and send a help packet. Hey, there's an opportunity for the next guy who wants to make a new micro linux distro that does something unique - the more silent, slim, and faster the better. Maybe even a fake Windows splash screen while it's doing its business.