Just to make clear - the O-A is only issued for long stay for those meeting 800k/65k financials and over age 50 - there is no lower financial if married or have child.

Is that a correct statement? I thought the marriage and supporting a Thai (my son) was 400,000b.

Lopburi3 is correct !

The 400,000 relates to an extension of stay(not a visa) based on marriage.

The O-A is a special long stay visa and is currently issued for those meeting retirement conditions. It is not available for marriage/child - for that you would obtain non immigrant O visas and then extend at immigration inside Thailand at the requirements for marriage or child of 400k. So if you want to obtain the O-A in USA you will have to do it for retirement and meet the 800k/65k financials.

Are you saying I cannot extend the OA based upon marriage or supporting a Thai? If that's true, can the OA be converted to an O at some point? Or, can I obtain an O from somewhere outside Thailand but not having to go back to the USA?

No I am not saying that at all - but I would not guarantee it either. I was speaking that you can not obtain an O-A visa with less than the 800/65k financials.

Single and multi entry non immigrant O visas are currently available for marriage at nearby Thai Consulates if required.

The O-A is a special long stay visa and is currently issued for those meeting retirement conditions. It is not available for marriage/child - for that you would obtain non immigrant O visas and then extend at immigration inside Thailand at the requirements for marriage or child of 400k. So if you want to obtain the O-A in USA you will have to do it for retirement and meet the 800k/65k financials.

Are you saying I cannot extend the OA based upon marriage or supporting a Thai? If that's true, can the OA be converted to an O at some point? Or, can I obtain an O from somewhere outside Thailand but not having to go back to the USA?

A single entry non "O" visa is obtainable from Vientiane, Savannakhet or Penang.

Apply for an extension of stay based on marriage during the last 30 days of the 90 day stay the visa will provide.

If you want an O/A visa then that will have to be obtained in the states. If at the end of the stay provided by the O/A visa you wish to apply for an extension based on marriage you can.

Are you saying I cannot extend the OA based upon marriage or supporting a Thai? If that's true, can the OA be converted to an O at some point? Or, can I obtain an O from somewhere outside Thailand but not having to go back to the USA?

No I am not saying that at all - but I would not guarantee it either. I was speaking that you can not obtain an O-A visa with less than the 800/65k financials.

Single and multi entry non immigrant O visas are currently available for marriage at nearby Thai Consulates if required.

Once you have non-immigrant visa of one category, you can extend at local immigration for a reason in a different category (if you have all of the paperwork). Can someone confirm this?

The other question about getting non-o for retirement/visiting thai family is fairly easy at neighbor thai consulates (Penang, Savannakhet, vietenine). No need to go back to usa.