Have a Chinese teacher at my school, who's looking to goto BKK next week to get his Non Immigrant B.

I was sure though, that you could only get them at Thai Embassies, and not in BKK. He seems relatively sure that he can just goto BKK though, and he can read / speak Thai so am going to assume that he is better positioned to find out these sorts of things than me.

However if you guys can please confirm for me that'd be awesome, as I'd like to save him a trip to BKK if possible.

he can get an extension not a visa.

He can only get an extension of stay with a non immigrant visa entry, job, work permit, paperwork from company and at his local immigration office (from post it would seem this is not Bangkok). If Bangkok is out of area and not the local immigration office the only reason I can think of would be to obtain non immigrant visa entry/change of status so that a work permit and extension of stay can be obtained. Not sure that immigration would provide but perhaps school knows. For this local immigration offices sometimes send person to Bangkok if qualified.

hmm..... told him that you guys likewise said he needs to goto an Embassy, not BKK. But he said one of his friends apparently went from a tourist visa, to a Non Immigrant B in BKK, and one of the other farang teachers said the same thing

Guess I'll just have to wait until next week and find out what happens with him

(And yes, BKK isn't the local immigration office either, as we're in Isaan)

He converted his tourist visa to a non-immirgant visa. For teachers that is a real possibility, as their Work Permit doesn't take that much time.