If you want extra buttons, and you want really amazing ability to program them, then you might want to think about a touchscreen. I got one, and I love it (like you I also have an X-52 and Saitek pedals - but it doesn't matter what you have).
Go here, check this out. http://www.touch-buddy.com/forums/index.php
Software is free, and the hardware should run you about $200 or so. I got mine for about $150 plus $20 shipping.
EDIT: Actually this FAQ thread is really a lot better. http://www.touch-buddy.com/forums/faq/18-master-faq.html
You can try the software without having a touchscreen, by the way, just using a second screen (or connecting a laptop) and using your mouse to click on it. That way you can try some of the cool profiles that have already been created. But you will want a touchscreen before you are done.