I want to use CSS text-overflow in a table cell, such that if the text is too long to fit on one line, it will clip with an ellipsis instead of wrapping to mult
It seems that if you specify table-layout: fixed; on the table element, then your styles for td should take effect. This will also affect how the cells are sized, though.
Sitepoint discusses the table-layout methods a little here:
http://reference.sitepoint.com/css/tableformatting