Just Got In A Midi Shield for the Arduino

I ordered a Sparkfun Midi Shield the other day along with some appliance lights that needed modification.  The midi shield came in last night.  I was a little disappointed when I saw the baggie and noticed that it did not contain any Arduino headers.  Fortunately, I have a Micro Center close by that carries the headers so it shouldn't be any issue with getting some to get the midi shield built.
What do I have in mind for this device?  I am planning on making a midi swiss army knife to use with my existing midi equipment.  Among the things that it should be able to do is swap channels, integrate well with the midi foot controller, etc.  I haven't really thought of all the applications just yet.  Some possibilities include the following:

1. Midi Thru


2. Midi Channel Translation


3. Arpeggiator


4. Midi Channel Merge

The Midi Shield is next to a Sparkfun Power Supply which obtains power from an old ATX computer power supply; neat concept.