BasementCat

Sorry for taking long to respond. Yes, I used Amazon Global Program. If you check their FAQ, you will see that additional 400 USD or any other amount in customs fees due upon the product's arrival is not an option:
"What if the actual Import Fees are more than the Import Fees Deposit I was charged?

For  items sold by Amazon Export Sales, Inc., you will not be charged any  additional fees if the actual Import Fees exceed the Import Fees Deposit  we estimated. For items sold by Merchants, please check the applicable  Merchant's policies."

I was wrong in my previous post regarding possibility of extra charge.

No Thai company should be involved. Amazon's Import team will arrange payment of import tax on behalf of yourself, fast and efficient. Be sure to purchase from Amazon and not from resellers (this information is available on product page). After you chose a product on Amazon.com, you will be able to see estimation of delivery cost as well as import tax, depending on your country and its tax law. Then you proceed and pay this estimated amount. Amazon confirms your order and ships your parcel. They will let you know if the parcel will require payment of any additional fee at the customs, and you'll pay it later on. This is a very rare occasion however. Buyers of child strollers should not be concerned.

In my case I paid 8'000 THB in one installment by credit card, and Amazon paid all of the import tax etc. I paid Monday evening, and Friday morning I had the stroller delivered to my door step. Mind you, it was a huge box weighing appr. 12 kg. No additional costs whatsoever.

Come on people, just order a stroller from Amazon. I ordered a Graco Quattro Tour (160 USD on Amazon) 3 months ago: appr. 8'000 THB including shipment, import tax and the stroller itself. Compare that to 25'000 THB in Central! Took 3 days from the order date to deliver to my doorstep in Samui. The only problem is that not all models are available for sale outside the States. I was amazed that the price of delivery was only 1'000 THB.

A couple of years ago I asked in BKK Samui and Thai Inter, they said either can't do or have to send to BKK and charge outrageous price. I ended up going to a lab in Nathon, they drew blood, sent sample to BKK and then faxed me the results in a couple of days. Reasonable pricing as well. The name is AngThong Lab I think. Take a left turn on the traffic lights next to the Immigration office (if you're heading out of Nathon), drive 100m or so to the waterfalls and you'll see a small house with a sign on your right.

I would second Dr Sankiat here, he is awesome. I had some complications which he handled perfectly and delivered my baby safely.