Well it's my turn to say a big thank you for this script. Using it to solve my shading switch problem.
If I could be so bold as to make some comments/requests:
-Esc didn't seem to quit the whole process, it just cancelled the current render and moved to the next one
-Option to choose the camera to render would be great
-I tried adding my above "exr" support, but I'm getting files called myrenderimage.exr.img so obviously I'm doing it wrong. So it would be great for exr to be included in the list.
-I don't know if this is possible, but specifying the number of render threads... by default it uses all of them and sometimes I like to batch render with all minus one.