> eFuses, maybe? Or a bit of battery-backed SRAM. Lots of devices have a small amount of hardened storage for e.g. encryption keys. FPGAs supporting bitstream encryption and Atmel's ATSHA device line are examples.

To clarify, I was referring to the status quo of current discrete TPM implementations, from a bigger picture perspective, there is certainly room for improvement.

Also I am not sure the current TPM standard is compatible with that idea at all. Operating systems set up their own TPM sessions, so there would need to be secret storage only available to a specific operatings system, e.g. similar to what TPM provides, and we are back to the chicken and egg scenario.