How about reversing the scan in the camera (a bit more work!), then
overlaying normal (forward reading) text to a 'standard' scanning
monitor...  Of course this means you need to do the Hdrive swap as
suggested, or use a different monitor...

I assume that the video feed is composite video+sync, so there aren't too
many choices (only one or two mfrs for composite) when inserting the char
overlay - unless you decode the video, then add the overlay and re-encode
it again.  Component count will head north with this approach.

Reversing the CCD scans are sometimes VERY easy.  I have a sony camera with
a small switch on the PCB to reverse the scans.  Worst case may be
reprogramming the local scan clock generator (no fun).

Of course you could go for the original idea of reversed character bitmaps
!
Good luck

MC