View the page source to see the 'fix'. Note that I strongly advise people to comment out the white space instead of using a CSS solution, but if that's not possible, this is my best attempt.
Each example box is 200px wide.
Based on this idea, but with my spacing fix applied to solve one of the problems with it.
Without spacing fix:
Without spacing fix and % boxes:
With spacing fix:
With spacing fix and % boxes:
And for comparison:
Commented out white space in this case prevent the technique from working: