There are use cases when an entry in the namereg would be desired to be permanent without excessive cost of buying the name til the end of time.

for example ABI storage on chain when creating a contract you might want to make a permanent abi entry so the dapp is essentially self describing.

There are a couple questions to answer:

How do we properly control this - likely answer another permission but without the ability to write a forwarding snative contract...
What kind of constraints are there? I'm betting none except those imposed by the magical non-existent contract above
What is the policy of overwriting the permanent entry? - Anyone with permanent name (pname) seems to contradict the whole premise. Writer seems reasonable. Maybe pname-del should be another permission?