Originally Posted by
linoleum
From that slideshow, it sounds like in my original example, the 2nd nether portal at 40,10 would return you to 320,80 which is more than 128m from the original overworld portal, so it actually would create a new one. In other words, we only even need to take 16+1 paces in the nether before it is far enough to create a new overworld portal, which is not bad at all (although even a 32x32 "room" is pretty big).
Oh you added more:
This is the best idea, but of course...having portal travel from overworld 80,80 to 100,100 isn't all that impressive. ;)
To get a good "fixed" portal link, we need them to be spaced reasonably far in the nether, too.
For example, 10,10 (to 80,80) to 500,10 (4000,10)...it's still a better to walk 500 than it is to walk 4000, it's just that making a safe path of 490 blocks through the nether might be a little more difficult. ;)
p.s. For comparison, on the old map, it was only approximately 1000 blocks from spawn to the farthest "real" stuff we had in any particular direction. So even getting a portal to take us that far would be great.