Does anyone have any info about how hard or easy it is to get a NON-IMMIGRANT B at either Vientiane or Ho Chi Minh City, especially if I have all the paperwork properly prepared by my employer in Phuket? I'm an American passport holder...

Penang is much closer to Phuket and relatively straight forward, providing your paperwork is good.

If this is a new WP then along with all the other required papers (see link below) you will need a successful Work Permit Application to be filed, plus certainly in the case of Penang you also need a Letter of Approval from Phuket Labour (I also recollect seeing this posted for Vientiane).

http://www.mfa.go.th/main/en/services/123/15388-Non-Immigrant-Visa-%22B%22-(for-Business-and.html

Most recent posting I could find re Ho Chi Minh City for a Non 'B' was from 5 years ago, your only option there I guess is to try diecrt phone or email.

One of our staff got his Non-B at the Ho Chi Minh Consulate a few weeks ago. Their paperwork requirements are quite strict but if you are going to be subsequently applying for an extension based on employment you will need all those documents anyway.

Link here: http://www.thaiembassy.org/hochiminh/en/services/2884/34919-Non-Immigrant-Visa-%22B%22---To-Work-in-Thai.html

It is a quiet Consulate so no queuing and despite being strict the staff there are cooperative. Our office was able to email scanned copies of all documents to them in advance which they approved therefore avoiding any surprise demands.

As I recall the application was submitted in the morning and ready the following day at 2pm.