Here's my implimentation of your idea (which isn't too bad). 
 I included 3 options for a date legend - one at the top of the table (which I admit is somewhat clumsy - but the font could be shrunk if people like it), one a simple single box ("week 1" "week 2" "week 3") below the main table (could be above if people prefer it), and one a running table that notes the date with each color.  Let me know if you like the color idea, and if so, which legend you prefer  
 Talk:On The Lot/Elimination tables#TheHYPO