With a colon? Also, to get your spacing:
<td style="position:relative;">
<div style="width: 10px; position:absolute; top:10px; bottom:10px; background:grey">
</div>
</td>
EDIT:
I don't think it's possible without specifying an explicit height. The solution in the original question that you pointed to does not actually work. position:relative
does not seem to apply correctly to table cells. This could well be intentional and part of the spec.
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