custom batch scripts for merging , bitmap change on hundreds of max files

I might have a project that has 500 max files and about a 1000 diffuse maps, each max file needs to be rendered 1000 times with all those maps, so there would be 500k renders..

so i'm looking for advice on existing or custom scripts to handle this, i think they are mostly simple batch scripts, for instance:

script 1: merge a camera , lights and change render settings to all 500 max files ,
so this would be, open file, merge( or create)camera and lights, change render settings, save as..

script 2: fix mapping to be made uniform in all files, so this would be, open file,select all , ungroup, select geometry, add reset xform, add uvw map, save. And the same for all the 500 max files.

script 3: adding the 1000 maps to each of the 500 max files, so this would be, setting a folder for max files and textures, and open first max file and change diffuse channel bitmap, save as, change diffuse channel bitmap, save as, and so on for all the textures, then open the second max file and do the same and so on for the 500 max files.

A better option though is to just change diffuse bitmap and render so there are 500k renders output but not 500k max files.

any advice would be appreciated.

thanks