Years ago I downloaded a modified batch render script, Batch Render V2.cs, that allowed you to name the individual rendered files.
I've been using this since V12 or 13, I'm not sure which. When I tried to use it today in V20 the menu was so small I couldn't use it so I dove in and doubled the size of each of the menu related variables & that did the trick
How can I share it here (the upload button won't accept it)?