Has anyone done this in Bangkok? What is the process, time frame?  Easy to do for the 10 year?

I'm in Mexico and got my 10 yr visa to China, used a visa company that specializes in Chinese travel and visas. I guess it doesn't matter where you are, a US passport qualifies for 10 yrs now. It took l1 week and I sent them everything by DHL.... they were very specific that the application had to be in a certain color ink (black or blue, don't remember) and NO ERRORS or t would be rejected.

I'm sure such a place exists in BKK 

I’d call the visa section of the Embassy and ask. I think the answer will be yes as long as you have your passport, a return travel ticket, and info on where you will stay, etc.   

as floridarob notes they are picky about ink colors. 

Its outsourced-like so many countries do now, and cost a lot more, but I think for US its always the reciproke of what US charges itself-used to be132US$. And, at least for me, (NON US) a lot of useless hollabaloo, even more as fl-rob says or what TH asks to see and receive in print. Main aim is to sift out those of perhaps former Chinese ancestry as potential unrestmakers. Thus also this means calling embassy is pretty useless. AND often non-Thai are either simply refused or sent through so many loopholes they simply quit it.

IN the end it turned out for me to be much easier in HongKong, pay double and you can even get same or early nextday service. But that was only for single tourist visit.