Keep at it, David! You've got a great product and we're getting the word out. You should post some pictures and videos on here, too.
For anyone interested, I've got a thread here showing the DMD Extender in JP, including a solution for a DMD LCD and an apron screen simultaneously!
The cost is comparable to a new plasma and I don't imagine I'd ever go back to one of those for any game I can fit an LCD into. It's also a great product for tinkerers, DIYers and those who like flexibility. Don't let someone else decide which colors are good together in your game, make your own choices!
One enhancement that I think would make configuring the DMD Extender a lot easier would be real-time adjustments to colors, screen position, and screen size. I envision plugging a USB keyboard or mouse into the RPi and being able to make changes on-the-fly. It would alleviate a lot of the guess and check to getting the screen positioned correctly and getting colors to look right on the LCD.
Again, great product! Thanks for making it!