Of course it can be done, but I wouldnt recommed it unless you are planning to get a Thai health insurance. A little know fact is that if you have some kind of international insurance you will have to have it certified by your embassy for the extension after a year. Many embassies are simply not going to do this. Therefor I would recommend the non-o instead, which is basically the same (with a little more effort in the first year) minus the health insurance requirement.