Okay, so for that terrain system, I've done some performance testing.
The current generator is written in native TorqueScript and is between above-average and fast.
I haven't put it through extreme testing, though.
I've tried rewriting the generator in Python and done some heavy performance testing.
It can generate one chunk in around 0.005 to 0.01 seconds. That is extremely fast.
I also tried 4096 chunks at once (1048576 iterations), which it finished in 35.6102984126 seconds.
Based on what I've gotten from these tests, I'm going to make a networked or file-based system where all the calculation is done outside Blockland.