Using my charms at a smaller branch, I was successful in opening the account today, even w/o residency.
It took an hour though, it's a very sleepy town - even getting a SIM card took 45 minutes yesterday - and I'll receive the card next week. Changing money is still better on the black market though, got a tens of millions of kip from a friendly gold shop for my dollars. So in the end, doing it the 'local way' one can get the card for $20 (plus $20 per year afterwards), and luckily I am still able to persevere without an official residence anywhere.
Regarding residency, you can find agencies that help with the process in every bigger city, some even offer their services on FBIbook. But you must be here on the ground to actually get it, at least to 'activate' the visa and receive an id card. Surprisingly, the fee varies from province to province and ranges between $390-$590 per year.
Opening a business is possible as a sole foreigner as well, minimum investment requirements vary from kind of business, to open a restaurant (as a foreigner without local partner) one is required to invest minimum around $15K (depends on exchange rate). Having said that, there might be other in-official fees involved afterwards (cops/gov. people ask for handouts), as I have heard from some entrepreneurs.
Gonna head to the riverside for some coffee now, missed the night-market delicacies yesterday.