All visas obtained through an agent which skip the financial criteria are "dodgy". However, I don't know if visa agents in Thailand will handle the OX due to the stringent requirements, and I'm sure if they do the price would be over 70,000 baht.
Most got it from Sydney because the finances didn't have to be moved to Thailand. Getting it in Thailand means shifting the 3 million Baht (or whatever it is) to Thailand. I don't know if visa agents offer this visa and stump up the money like with the 800k for the O visa. Somehow I don't think they would