Verifiable git archives?

It's possible, in principle, to shove enough metadata into the output of 'git archive' to allow anyone to verify (without cloning the repo) to verify that the archive is a correct copy of a given commit. Would this be considered a useful feature?

Presumably there would be a 'git untar' command that would report failure if it fails to verify the archive contents.

This could be as simple as including copies of the commit object and all relevant tree objects and checking all of the hashes when untarring.

(Even better: allow subsets of the repository to be archived and verified as well.)

--Andy