Hi there, 
  
I know this is an old thread but I'm interested in this idea as well. 
  
I currently use a Doepfer MAQ 16/3, Sequentix P3 and Analogue Solutions Europa 
  
I've also been playing around with the Beat707 Arduino Shield and re-programming it a little. 
  
I want to build my dream drum sequencer that will hopefully look something like this... 
  
 
  
I was initially thinking I would build it based off an Arduino board but now I've discovered Midibox I'm wondering if this would be a better route. 
  
Anyone got any thoughts on this or any other helpful links/info?