Anyways, I do plan on making it go on forever. (including height wise if enough people want)
Thanks for the positive comment : D
Forever height wise doesn't seem as good.
In my opinion, it would be better to add different styled areas further down.
So, Stone area 1/3, then Some obsidian or something and bedrock 2/3, and maybe a hellish kind of world 3/3.
But the areas could be very big, giving more of a challenge.