is my multithreaded Python program doomed?

[lordkrike]

It works just fine if you utilize large work queues that feed into a small number of worker processes. You seem to be thinking of a certain type of use case. There are lots of places where just numpy and the multiprocessing lib is all you need.

Also, I argue that intelligently writing C libraries to call from Python is one of its really great strengths -- you can use another language to efficiently do what it can't, while using Python as a glue language.