Hey, I've had a look myself but no real luck either. Penguin does sell blank matchbooks, but last I checked they were out of stock. If it still is out of stock, at the very least maybe one of the Penguin staff there could help you out. Other than that I haven't really much clue.
Sorry I couldn't be of more help, and let me know if you find anything
Sorry I couldn't be of more help, and let me know if you find anything