Is there a way for a user to verify themselves when following a checksum link?
I dont remember this session at CiviCon London. By any chance, are you referring to the email address validation on unsubscribe (the user has to enter their email address to unsubscribe)

I suspect the way the above would need to be done, would be:

a. Take the user to a different validate and confirmation page.

b. On confirmation, send the user to the real profile edit page

c. Add a hook to the profile edit page to ensure that any user coming here  has come via the confirmation page