I don't think there is one currently.

No, there is no such function. It's been suggested before but it's complicated and needs a lot of coding according to Scrubs so don't expect it in the near future, if ever?

Please, reconsider to implement a duplicate with MIRROR function. It will be VERY useful for Technic designers!
Thank you.

I'm unable to make z axis rotations using the MacBook Air keyboard. Which are the "keys next to page up and page down keys on an apple keyboard"?

I have never seen a build tool that's supposed to be used to build vehicles without a mirror function.
Can you donate anywhere so i can maybe motivate them to?

Maybe it's possible to mirror it once it's in Blender, flips the normals and that should be good enough. I'll experiment and see how it does.