I was told that the Thai Embassy in Vientiane does require a criminal background check when applying for the Non O visa. It was previously reported here that the place to go to obtain such a check is in Bangkok, for those of us that prefer to not make a trip to Bangkok another solution is to visit the local Thai police Forensic Science office. They will do the background check for 100 baht, but I regretfully learned it takes 1-2 weeks for the report. Anyhow I hope that information may help others.