Can I do a DTV visa run extension through a land crossing in Burma?

yes, you can do visa runs organised on DTV with

@MY *********************

No problem with DTV.

Just so you're clear you're not extending anything 😮 What you're doing is exiting the country to get off the current stamp you're on and entering on a NEW 180 day entry stamp. It's not any type of extension just a new entry 🙂

Now as to your question;

The only land border between thailand and burma that's open is the one you get to by boat from the Ranong pier (Ranong/Kawthaung)

It's a tightly controlled exit/entry point and you'll pay what the boatmen want or you won't get out of thailand.

If I'm not mistaken (which I could be 😉 ) it's about 2500baht to bounce out/back at that crossing.