Can you obtain a re-entry permit from any immigration office in Thailand, or is a TM30 required?

That depends on what you are trying to get a re-entry permit for.

Generally if you have an extension from a specific immigration office, you're only going to be able to get a re-entry permit from that office, or at the airport.

But if you have something like a permission of stay that is based on entering with a visa, so it was not given by an immigration office, you can use any office as long as you have a TM30 for that office.

You can get one at the airport

Ask for a TM30