one issue i was having with this was the fact that 'height: 100px;' was not only limiting sigs to 100 px in height, it was also reserving 100px in height. the result was a 100px high sig div even if the sig was a single line of text. this was not aesthetic.
i changed it to max-height, which is something approaching what most of us would be looking for i imagine.
i also added zero padding, although its effect is questionable. i was hoping to avoid this situation where a 105px 'allotment' is required to display a 100px sig without scrollbars.