Thanks, yes, the scanner works in Image Capture, which means it's supported by the OS. But I need the scanner to work as a TWAIN source or otherwise go direct to PDF OCR. Image Capture & Apple built-in drivers don't do that.
Anyhow, thanks everyone for their input, but at this point I think I'm going to give up and do my scanning in Windows. It's just not worth spending any more time on this. Shame on Epson for such poor OS X support.
