I just got the insurance required from a company outside Thailand. They signed the required certificate as well. Details below:
I stay in Thailand for six months every year and spend the other six months in the US. I always get an OA visa because I truly don't like doing visa runs, (ME tourist visa I would still need a visa run and also I would need to be employed or a student). You can make an OA Visa last two years if you return to Thailand prior to the Visa expiring. This year, I needed a new OA Visa. The confusing part to me was I can get my visa prior to Oct 31, but I will be arriving the end of November. There have been multiple opinions on whether I would need the insurance since it comes into effect after the 31st, but arriving after that. Not wanting to take the chance on being rejected when I arrive in Thailand, I decided to secure the insurance (I usually got Travel Insurance, which frankly had a lot more coverage). I secured a global insurance plan from Regency they have specifically for Thailand. They sent me the policy and the signed legal document i need to confirm the coverage. No issues at all.