flippyneck, I like rla/rpf because specifically to make depth images in after effcts and combustion is flexible. I had tryied that zbuffer plugin and the method of giving to all objects the same whithe/black material and control the focus point with an empty, but those are not as flexible than rpf (this let you control the focus point inside the compositing app). So basicly I am looking for that way to interactive control the focus point value.
Maybe I am wrong, but I believe rpf/rla is the standard for the work you are doing, not only 3dsmax gives this export option, but lightwave and maya and maybe some others. I found some of it history here.
Lightwave´s extended rpf export.
And some another tinfo from SGI (old info from here, open with wordpad).
This is the ftp were I found them.
This is where I found that ftp.
And the url where I found that bunch of ftps.
I don´t have a clue of coding (but hope it helps), and I have few time of knowing this file format, maybe somebody else has furter info.
I know the depth is just a part of the output you are working on (I don´t know how to work with the others yet)
For finish, would be so good, if this could work within blender´s secuencer to make it powerful and avoid the use of commercial packages.
I Hope to be good enough with my english.