Filter world seeds based on world spawn location

When generating a new world, you should be able to specify conditions about the location of the world spawn, and the game will keep trying different random world seeds until it finds one that matches all the fondictions.  Conditions I'm interested in:

1) World spawn is in a certain biome.

2) World spawn is at most X chunks away from a village (or 0 chunks away to specify that the world spawn overlaps with a village).

3) World spawn is at most X chunks away from a certain biome.

And I'm sure that there's other types of conditions that could be used.