> (besides the random pings from Ambisonics)

What do you mean by that? Ambisonics is a very viable technique for positioning audio sources in 2D/3D.

Hmm. How can I position an audio source into a 3D world?

Well you don't literally. You feed the positions of the objects in your 3d world into an audio positioning/spatializing system (ambisonics or other). Rendering 3d graphics and rendering audio will be 2 separate subsystems of your app. Generally, you'll calculate the relative position of the sound source to the listener, which is usually the same position as your 3d camera. This gives you a direction (expressed in angles or coordinates) and/or a distance which can be mapped to audio controls, from simple panning and volume control to advanced ambisonics etc.

Have a look at for example ICST's ambisonics objects: http://www.icst.net/research/downloads/ambisonics-externals-for-maxmsp/

You could also check out COSM, which does integrate 3d graphics and audio to a great extent: http://www.allosphere.ucsb.edu/cosm/ (I think development of it stopped at Max 5 though chances are it runs fine in Max 6)

Yes, I can confirm COSM runs fine in Max 6 (6.08 at least) provided cosm.mxo is located in one of the MAX search paths.