Yes , it is possible , I did mine a few weeks ago , claimed back 28,765 baht , its quite easy , just go to the bank , in my case 3 different banks. Obtain a certificate of tax deducted for the past 3 years. Take this along to your " local tax office" , they will issue you a Tax ID card and after filling in tax returns for you ( fee was fir me 200 baht )
They send you a cheque which you take to Krungthai bank to cash. The whole process took me half a day .