You are missing your <tr> tags in minicart.tpl and the "rowspans" are messing up the table alignment. Try the following modification to minicart.tpl code, I managed to fit it nicely in my nav bar on one line.
minicart.tpl
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Code:
{if $minicart_total_items > 0}
<tr>
<td width="23"><a href="cart.php"><img src="{$ImagesDir}/cart_full.gif" width="19" height="16" alt="" /></a></td>
<td class="VertMenuItems"><b>{$lng.lbl_cart_items}: {$minicart_total_items} {$lng.lbl_total}: {include file="currency.tpl" value=$minicart_total_cost}</b></td>
</tr>
{else}
<tr>
<td width="23"><img src="{$ImagesDir}/cart_empty.gif" width="19" height="16" alt="" /></td>
<td class="VertMenuItems" align="center"><b>{$lng.lbl_cart_is_empty}</b>
</td>
</tr>
{/if}