As I'm reading that items shipped out of Thailand are actually liable to Thai export taxation, is the same applicable to anything you bring back with you when leaving Thailand to head back home? How much might one expect to pay? Specifically I'm thinking about arts and craft items.

I would think that exporting single items would not be an issue depending on what you declared for Customs. If you are shipping personal property this is not taxable. If you are shipping bulk items and multiples thereof you will attract attention for sure. Ship by container then have your paperwork ready.

Depending where you ship to - again if these are personal items they should be non taxable. Places like Australia now charge 10% GST on import but no idea of other places, but not on personal items.