Min-width and max-height for table attributes
To force min-height attribute for td you also can put invisible image in td, or wrap you td into div. Example for first case:
<td><img style="float:left;min-height:50px;visibility:hidden;width:0px;">12345</td>
For table cells the 'width' property should be used, as the 'min-width' and 'max-width' is undefined for table cells. See the specification:
"In CSS 2.1, the effect of 'min-width' and 'max-width' on tables, inline tables, table cells, table columns, and column groups is undefined."
To enforce the width, you may try to change the table-layout property to "fixed". The specification describes the algorithm pretty clearly.