The above seems to be incorrect on various counts:
In order to be considered to be granted a work permit for a foreigner, the company must have a registered share capital of THB 2,000,000 per foreign work permit. I am quite sure that you won't get a work permit for a "Farang" with a company of just THB 15,000 or 20,000. Founding the company with a registered share capital of THB 2,000,000 but only putting up 15,000 would not be exactly legal and the revenue department et al will have your butt for breakfast when they find out.
Work permits are NOT transferable. Work permits are always granted for the particular employment only, the employee (and I'm always talking foreigners here, because Thais obviously don't have to deal with the work permit issue) can not "take it with him" when he goes to work for another company. The work permit is not even valid if working for the same company in a different location than initially declared/applied for, i.e. if you've got a work permit granted for work at "X Scuba" on Phuket, you can't legally work under the same work permit at "X Scuba's" dive shop in Krabi.
If an employee leaves a company, the company is obliged to inform the labour department. If you quit your job, the work permit is revoked/void - and so is your business visa that is tied to it.