@Julien *****

Well with the price of a DTV you don't actually need to commit for five years. Why the OP does not want to visit the country for a short stay before pursuing that route is beyond me though...

@Osher ********

Some people in the banks for sure. But with BKK bank you can do it yourself also, even on short tourist visas, just be prepared to try several branches (in foreigner areas). It all depends on the branch, mood of the clerk etc.

@Charles *********

The return flight is a separate issue. In principle you are supposed upon entry to have a return/onward flight or other transportation ticket for every country or territory where you are not a resident. In practice this is enforced somewhat arbitrarily, some countries/airlines always ask for it others rarely/not at all. But normally you can still mitigate this if it should happen to you, you can just buy a fully refundable ticket on the spot and cancel sometime later.

There are 25 visafree countries which includes most of the big European countries incl. the UK. US, Switzerland and others need a visa