Originally posted by jonnin:

I don't think you will find this.
- mountain alone is nearly unheard of. Its rarely on the coast, always a buffer to the shore.
- large islands and single biome are also very low chance.

1 - i found some lone ( and big ) island mountains , them are rare yes but exist
2 - yeap its what i see , its almost impossible found everything in just one seed , but only plains islands are pretty normal , swamps rare and mountains very rare to found