For some time now, Thai Embassies in some countries have started to issue a real One Year Visa for Thailand, that allows you to stay in Thailand for one year, without doing visa runs every 3 month. The new visa is called “Non Immigrant O – A, where the “A” obviously stands for annual.
You may have to check with the Thai Embassy in your country if they would issue this kind if visa or not. It is interesting, that this visa is only available at Thai Embassies and General Consulates but not at the Honorary Consulates.
The requirements are almost exactly the same as for the one year extension of the old style Non Immigrant Visa. The only difference I can see is, that you may have the required money deposit sitting at the bank in your own country and not in Thailand.
Most important, you still have to be over 50 years of age or be married with a Thai or both plus you must meet the financial requirements.
Please do not forget that you still have to report to the local immigration office every 90 days when you stay longer than 90 days in Thailand.
For this One Year Visa, you don’t need a Re Entry Permit during the 1 Year validity. Every time you exit and re enter Thailand you will be given another year. But don’t confuse it with the normal extended Non Immigrant Visa O-M for which you definitely need a Re Entry Permit anytime you want to exit and re-enter Thailand.