If someone forms a Limited Company with a fully paid-up registered capital of THB 2 Million, and has job offer letter from that company at a salary of THB ~15,000 per month - which Thai consulate/embassy could give him a Multi Entry Non-Imm B?

It is my understanding that Penang/KL would work if he could present a work permit, but what if he hasn't got one yet?

As with anything to do with immigration, the powers that be make decisions that they "feel" are right. Columbo, Sri Lanka is supposed to be easy. Both Ha Noi and Sai Gon (Viet Nam) are easy for some things. You must check to see if they offer multiple non-B's. Kuala Lumpur issues multiple entries, but I dont know what their mood is. Check the board and find out which would be the easiest place to get a multiple non-B.

If someone forms a Limited Company with a fully paid-up registered capital of THB 2 Million, and has job offer letter from that company at a salary of THB ~15,000 per month - which Thai consulate/embassy could give him a Multi Entry Non-Imm B?

It is my understanding that Penang/KL would work if he could present a work permit, but what if he hasn't got one yet?

Non Imm visa would suggest you are enquiring regards a foreigner?

I understand foreign employees of Limited Companies have to have a minimum salary of 50,000 baht per month ? NOT 15,000 baht ?

I understand foreign employees of Limited Companies have to have a minimum salary of 50,000 baht per month ? NOT 15,000 baht ?

There are no minimum salary requirements to obtain a Visa nor a Work Permit. The minimum salary requirement applies only to a one year extension of stay.