All I really wanted was POSIX-style threads. I was prepared to properly deal with locking and mutexes and the whole nine yards. My Operating System supports POSIX-style threads in C, but perl's threading is a completely different beast.

You mention using 5.6.1. The threading model exposed in 5.6.1 is almost exactly what you say you want. A thin veneer over the POSIX threads API. Everything shared by default. Full access to all of the POSIX locking and mutex functions.

My suggestion to you, is to try writing one or two mildly complex applications using 5.6.1. This is the only way that you will see and understand the difficulties involved in trying to translate the techniques that you would employ using this api at the C level into programs that also have to contend with the realities of Perl's "fat" internal datastructures and inherently non-reentrant core apis.

Only then will you understand that you don't want what you think you want.