Fortunately, with the new 3D placement functions we just added to the code, it will took much less time to make it. At the time, we have not limited these functions to one action per cycle, so it will be really faster. We might eventually add a limit in the future for that, but we'll keep a setting somewhere to override.
So, as the first problem might be resolved, let's look at the second one.
For the world render distance (and loading distance) problem there is some ways :
(1) Render by parts. The advantage of this is that there will be virtually no limit.
(2) There is a way to change world loading limit and viewing distance. It can be changed in the configuration file (RenderingDistance_Horizontal & RenderingDistance_Vertical). One unit more will add 2x16 blocks(it's a radius) in horizontal and 2x64 blocks in vertical.
Unfortunately, you'll can't get really high in the Windows version as it will get out of memory and will crash. So it's not recommended to get higher than the standard settings(It may be nasty and appears to work... then crash after some time or when you move). If you want to use higher settings now, the only safe way at this time is the the 64 bit Linux version.
The Blackvoxel Team