Hi,
thinking about it I'm not sure it is feasible as the "change color to your rows" approach involves a main problem whenever two rows have the same value on the sorted column and you couldn't know which one is shown on top by our sorting algorithm.
Btw such approach consist on tracking the position of each row knowing the sort field and the sort values. Having such information you should store somewhere the DOM references to each row that is given through the onChangingValues callback and then change row colors accordingly. As said in the other post it's a little bit tricky.
Btw, I think that Dario's advice was the best one: you could use fixed height rows with no background and a background image to obtain the alternate rows.
You can see an example of a table with a background on our
homepage
HTH