Ok, fair enough. I'll go to Jomtien immigration tomorrow to see what they have to say. If they can't grant the visa with a 90-day rental agreement, then Savannakhet may be my only option anyway.
Thanks. The parental option is interesting - how would I obtain the decree of parental rights? That seems like something I should have regardless of my visa situation.
If I get the visa in Jomtien, then encounter problems later getting the extension, what options would I have? Could I still go to Savannakhet to get another O visa, or would that no longer be possible?
My wife and I own a small apartment in Bangkok (in her name only), so I guess one possibility is that we could use that as our address and process everything in Bangkok. The problem is that we don't intend to live there, and I've read that immigration sometimes visits the stated residence. What are your thoughts on that?
I'd like to avoid that trip to Savannakhet if I can help it, but if it is indeed the safest option then I should do it soon.