In the posts you refer to I believe the issue is not where the TPM is located. I believe the issue is where to place the secure "USB Hub".
I was struck by these presentations as they might imply that, apart from the motherboard mounted 1.1/1.2 TPM, we'll see a "Trusted USB Hub". To me this may possibly dictate a programmable, multiple trust domain device with, for security reasons, it's own O/S. Does it not?