Dmitri has documented the SysEx stuff. Have a go!
Development of the config tool will simplify the project and leave new users less prone to making mistakes, but unless it is open source how to maintain and support it?
Along with a few others here it seems, the first thing I did after assembling my megadrum was erase the firmware. The next thing I did was see how far down the garden I could drop kick the buttons. Just as I started to write my own bootloader up popped the Erase SysEx idea but, determined to have a headless megadrum I spent more time developing the bootloader to work without any button input.
Nearly done it occurred to me that I didn't need a bootloader at all so started looking at using the PIC as a programmer - I figured that a header board would do the business but dumped the idea in favour of a completely new PCB because I wanted by now to try and clock the AVR using a PIC io line. Besides I wanted to remove the unused regulator, the opto isotator and the LCD.
All in all I've really enjoyed the whole thing ...not sure anyone else has though