From November 13th 2015 onwards the new tourist visa will be available. The new regulation allows tourists a six months visa. Tourists are granted multiple entries during this six months period, for up to 60 days per stay.
Currently travelers can obtain only three re-entry permits with a tourist visa. But this new visa type will have no restrictions as to the number of re-entries, as long as a stay do not exceed 60 days.
Please see some further information under the following link:
http://www.bangkokpost.com/news/general/702720/new-6-month-visas-begin-nov-13-but-limit-stays