Neil,
sorry i didn't reply to your PM ref these carbon panniers but i was a bit pre-occupied with the move.
Were you aware that you can buy sheets of ABS in carbon look-a-like ? This might be a lower cost alternative if you wanted the look.
I used to use it a lot for box packaging using vacuum forming.
Panniers would be ideal for this process. but you'd have to stiffen
them up with bracing or an internal frame.
I remember helping to make a samsonite briefcase in carbon - the outers were replaced and kept the original clamshell locking frame.
I think samsonite make them in carbon now, but this was 15 yrs ago.
Phil