At first: great work, the tag looks like it is all I need. I am currently evaluating your tag for my project, so far it seems like we will use it.
However, I did notice some issues but then again, I might have a bit of a nasty use-case.
Based on certain data from the DB, I use JSP tags & pure html to create tables and charts on my page (the chart being a html table where one column is filled with a div, the div contains the images of dynamic width). To make things even more complicated, I have to use 2 divs: 1 to display a certain score in the chart and second one to create an overlay chart (standard deviation). So at first sight the complete chart looks like a mix between a bar chart and a gantt chart.
To implement this I use two relatively positioned divs in one td to produce the overlay. This works perfectly well when I display the page in HTML. However, when I transform this to PDF, the containing td cell (and the table row as well), gets blown out – the height of the row becomes about two times the necessary size and constraining the height using CSS of height attributes does not work.