Also, I suspect they removed the original Far Lands by going from single-precision to double-precision variables; the accuracy of single-precision is close to the 12.5 million block limit; double-precision has far more accuracy, enabling a vastly larger world size (millions of times) before the math goofs up or integers overflow*. Of note, some things still goof up because they use single-precision variables, such as the position of torch flames (in 1.6 anyway), but when I tested it I didn't get any of the jittering present in the Far Lands or Bust videos (your position uses double-precision now).
*From the Wiki:
The hard limit where chunks are overwritten is at X/Z of ±34,359,738,368, which is about 23% of the distance from the Earth to the Sun. At X/Z of ±2,147,483,648 (crashes at 2,147,483,439), item positions, mob pathfinding and other things using 32-bit integers will overflow and act strangely, usually resulting in Minecraft crashing.