Jordi, I suppose in the meantime you can do a border bounce to get 30 day visa exemption stamp, then apply a Single Entry Non B Visa when your accountant have all papers done.
Living in Samui, you can do a border run to Satun (going with an agency and paying extra 1000 for the stamp) then apply Non B in Penang.
In Penang you can also apply for a Non O based on parentship, they don't ask for 400,000 baht deposited in thai bank since at least 3 months BUT, as a financial proof, a thai bank statement showing at least 200,000 only and no matter if deposited just few days before.