What are my options for visa extension in Thailand if my paperwork is not ready before my current stamp expires?

The real question IS; once the company does give you the paperwork will you try to get the 90 day Non-B visa INSIDE the country OR will you go to a thai consulate in another country to get it?

The reason I ask IS, if you're just waiting for the paperwork to go to a thai consulate in another country you could get the 7 day extension denied stamp for 1900baht to wait for the paperwork

BUT

If you're going to try to get the Non-B visa inside the country you need a minimum of 15 days left on your current stamp to do it AND buying the 7 day extension denied stamp will NOT work in that instance because you have to leave the country when that stamp is up.

I'd say your best course of action would be to fly out and back in to get a 30 day visa exempt entry stamp. Especially seeing as you used your TWO 30 day visa exempt entries by land in a calendar year already :/

That would buy you enough time. ..

If you are already on a 30-day extension you can buy another 7 days for 1900 ฿. I think you might need some reason and I expect that you have that.

4 months and your paperwork is not ready ? :-(

You can get 1 Extension of Stay at each entry. The question is did you already applied for the Extension after your last entry? If not you can apply for Extension of Stay for 30 days if yes, you have to leave to get a new tourist visa or fly out and come back, You can only do 2 border runs a calendar year.