Batch Material Editor?

[Steve M]

My office just converted a collection of old AR4/3 material libraries into .ArMaterial files for use with nXt for AutoCad.  Many of these materials came in at millimeters instead of inches, are previewed on a sphere when we want them on a cube, and are a the wrong preview scale to boot.  I saw that the .ArMaterial files are legible in a text editor, and wondered if anybody has had any luck batch editing the material files to switch the units, preview object, and scale?  I assume that once switched the old thumbnail will remain?  Is there any way we might trigger a regeneration of the thumbnail as part of the process?

Thanks!