Here they are in order of newest to oldest.
The MAC 2011 Lackawanna / Steamtown visit - Designer - cantinagirl/SleepsInLakes

The MAC 2011 Lackawanna / Steamtown visit - Designer - cantinagirl

The MAC 2011 Letchworth Revisit - Designer - SleepsInLakes

The MAC 2010/2011 OpenEnder - Designer - Jeff S. (eaglescout40 - Son of SuziQ) 
The 2010 MAC New York Tour Logo - designed with input from everyone and drawn by Bruce (SleepsInLakes)
The MAC 2009/2010 OpenEnder - Cooperatively designed by - Doug R. (bummer72) / Brenda W. (skittles) / Jeff S. (eaglescout40)
The MAC 2009 Quest for Quebec - Designer - Brenda W. (skittles) / drawn by Bruce (SIL)
The MAC 2008/2009 OpenEnder - Designer - Jeff S. (Son of SuziQ)
The MAC Voyage 2 Vermont (V2V) - Designer - Stacy H. (CantinaGirl - Mother of JD!)
The MAC logo with web address - Designer - Stacy H. (CantinaGirl - Mother of JD!)
The MAC logo in white - Designer - Stacy H. (CantinaGirl - Mother of JD!)
The original MAC logo - Designer - Stacy H. (CantinaGirl - Mother of JD!)
The mirrored MAC logo (for the back of the shirt) - Designer - Stacy H. (CantinaGirl - Mother of JD!)
A truly old MAC logo - Designer - Lost to history
The oldest MAC logo - Designer - Lost to history