I was checking out the application materials and requirements for Non-Immigrant B/Work Visa at various Thai Embassies in SE Asia. One person who went to Manila noted that he/she (?) submitted three letters of recommendation from past employers (outside of Thailand) for his/her ap in Manila.

Does anyone know if letters of recommendation are needed elsewhere i.e,, Penang, Singapore, KL etc...?

See the link below re letters of recommendation for the application (Manila Thai Embassy):

http://www.bubblews.com/news/1781156-how-to-apply-non-immigrant-b-visa-in-thai-embassy-manila-philippines

It might help if some idea of what you are seeking to achieve could be given.

Are in Thailand now ?

Manilla has a reputation for being super difficult, so I wouldn't read too much into what they are asking for.

Note that a letter is required in the case of MFA Case 2.1 (2) Foreigners who wish to conduct business in Thailand.

The company letter is normally provided as a courtesy alone.