Don't know if this has been mentioned before, but you can now buy coloured T-Loc Systainer Latches. For all you Festool zealots with a garage full of systainers, you can now colour code them. 
http://www.leevalley.com/en/wood/page.aspx?cat=1,43326,68749&p=70855

http://www.leevalley.com/en/wood/page.aspx?cat=1,43326,68749&p=70855