Does anyone know of a site that lists the requirements that a taxi must meet in order to be a licensed taxi?

I don't think thats anything a Thai would look up on the Internet so i expect not available. Your local LandTransport Office should know and i suspect there are regional variations(there is on most things it appears).But you walking in and asking i think would draw a blank and total disinterest as falang cannot drive one, so a Thai freind is the answer but even they might struggle if the local Taxi business is a closed shop so to speak.

End of serious part now frivolous section before others get in, requirements for taxi-

Every panel including roof dented, at least one front wing flapping bootlid tied down with string ,so many Buddas etc hanging from rearview mirror impossible to see vehicles pulling out of side turnings hence dents, semi slick(for varying road conditions)tyres mounted on a mixture of steel and alloy wheels but every one different, lights non operational apart from one full beam and one rear definetly no brake lights or indicators, smokey engine.

it also needs to be two tone.

rust and colour

omnipresent lao khao and M150/Red Bull/Lipo so they can drive for 36 hours straight.