I've been in Thailand for seventeen years, married to my Thai wife for sixteen years and have a fifteen year old daughter, who holds Thai and UK passports. I have a work permit and my visa extension is based on marriage. This extension works fine, but prepping all the documents (which change on a yearly basis), submitting the application and then waiting for a month for the decision to come back from Hat Yai is a bore. Can't retire yet, so need to keep the work permit. Question!! Are there any other visa extension options? Is a visa based on dependence a possibility?

There are really no other options for you. You could apply for an extension based upon but that is very complicated and requires a large stack of paperwork. 

You could apply for the extension based upon being the parent of Thai but it has the same 30 day under consideration period and financial proof.

Thought that might be the case. I'll stay with the marriage based extension for now. Thanks for the reply. Keep well.