Visa For Accompanying Family

[KenW]

I am a 40 year old american citizen. My wife is Salvadoran and we have two young children, both holding US passports. For the past several years I have been flying back and fourth between central american and SE Asia for work. I have finally decided to try to move to the region with my family to cut down on the time we are apart. We were looking at setting up a base in Bangkok (but not necessarily working there) as it has a lot to offer as a family.

I heard that I could apply for a multiple-entry non-immigrant visa 'B' by getting a supporting letter from my company saying that for business reasons I need to come in and out of Thailand. I was then wondering what type of visa could I get for the rest of the family. Is a type 'O' visa the correct one for my wife. And if yes, should the request for a visa for her be included in the letter?

These visas would also require us all to leave thailand at least once every three months, correct?

Thanks

[KenW]

I guess my question really is, can my wife/kids get an 'O' visa if I am not residing/working in Thailand.

Also, is it possible to be a consultant in Thailand if not associate with a Thai company or a representative of a US company without opening a TRO?

Thanks