Or is "true" multithreaded applications pretty much out of the question?

It's perfectly possible to create multithreaded applications. It's not the threading that is biting you, it's the sharing of objects.

For reasons of architecture which are too boring to repeat, you cannot (directly, and you don't want to know about the indirect mechanisms), share objects between threads. You can share data--that is scalars, hashes and arrays. The trick is to pass data between the threads and create objects within threads--for the exclusive use of that thread.