This is another mod born out of a need of my own.
If you want to change your map size after the start, this is your mod.

• change map height or width independantly
• can also remove a map limit set on game start
• starting area can't be resized (only chunks beyond the borders)

Walk with your player on the chunk it should be the limit. In direction south or west one safety chunk is added to the limit to avoid player deletion.
Press SHIFT + CONTROL + W to set limit on width, press SHIFT + CONTROL + H to set limit on height.

If limits are set and the key combo is pressed again, the limit gets removed.