Also - upon submitting my B Visa Extension application - they said all was in order but it had to go to Bkk for final approval. I got a 30 day wait stamp. Then was fully approved at the 30 day mark. This will not likely have an effect on dependant stamp - likely will get the same 30 day wait.
David - you could do what you described if you opened a Thai Registered Company with a Thai partner(s) owning 51%. And getting a Non imm. B Visa and Work Permit. But it can be a costly venture with ongoing costs. Or, I believe - if married to a Thai and she has a company (easy to do for a Thai) and you work for her.
Then look up Thale Ban National Park in Satun Province ... There is a border checkpoint there. A very laid back border crossing... You may just want to go there for your border bounce.
As it stands now employees with a B Visa and WP can only get a one year Extension of Stay at the local immigration office. This B Visa Extension requires fairly heavy documentation supplied by the Employing Company, taxes paid, company registration, last annual audited financial report, Thai Employees social taxes paid and more.
People have posted here calculating how to get maximum days out of a METV. Some suggest only using the 60 day Permissions to Stay (and only using one 30 day Extension at the very end - after the last border bounce to get the last 60 days.