You can open the account as part of the application for residency, once you have a precaria.
As far as rentista goes, I know someone who has a foreign corporation and sends the required minimum amount through this corporation, as his earnings that qualify for the residency. You don't send all your money down that way - just what immigrations requires for the residency. Of course, you have to start a corporation, put the money in the corporation's bank account every month, and send it down - on top of that you have to have an accountant sign off on the required paperwork stating that the money is indeed dividends or some other kind of "passive" income that qualifies, which can be a problem if you are "tricking the system" in this way. Said corporation would need to be in a country where you can pay an accountant to say what you need it to say, and that in and of itself may cause some issues here as to its acceptability.
As far as nomads go - Personally, I'd hate to be one who has no choice but to pull up the stakes every six months, but it would be doable. Cost a lot of time in finding a place to live every time you did it, or to buy places where you could always stay when you were there (along with problems associated with that, like trying to sell your property here, for example, when you'd had enough). If money was no object, I suppose an apartment in two or three cities around the world would be cool - but if I had that kind of money I probably wouldn't have to work full time any more!
But that's me, I'm more of a homebody; I like to be established and have a reasonably solid base from which to travel, when I feel like, or can afford, to travel. I like having my desk (huge, L-shaped solid wood, nicely finished, etc - plenty of space for everything except my elliptical trainer
), my two monitors, my computers, my nice speakers and my elliptical trainer (and that's just in my office!). When I first came here, I had a laptop and worked on the kitchen table for a year and almost went nuts. I even bought a cheap desk at one point so I didn't have to leave crap on the kitchen table when it came time to eat dinner with my girlfriend (who later became my wife) and carried that to a couple of temp apartments until I started renting long term. I like having my own glasses, dishes, etc, not having to worry about "checking out" and "checking in" every so often, etc.
