there is a <caption>...</caption> which can have its own style properties. I usually prefer to assign captions their own class. for example, <caption style="background-color:#00ffff;">Statistics for 2009</caption>
it goes right under the table tag.
<caption class="tableTitle">Statistics for 2009</caption>
there is also the capability to merge cells.
<tr><td colspan="2"></td></td></td></tr> (0 does remainder of group. there is also rowspan)
and the source view needs color syntax highlighting to make this an effective source editor.
crimson/emerald uses XUL to do this I think, and is configurable.
also, it consider supporting HTML5 tags since people are already using HTML 5. (I am, and so are others)
you might want to have a preference thing where you can set the DOCTYPE to HTML 4.01 or 5.0.
5.0 degrades gracefully. but the standard isn't finished yet, and it won't be for years to come I hear.