Per my earlier packet visualizer post, I have an app available for Mac OS X users to download. You can grab it here:
http://sintixerr.wordpress.com/pkviz-packet-visualizer-and-animator/
The app takes tcpdump ascii-hex output (the -X option) and animates through all the packets in a file. It splits the packets into bytes, with position in the packet providing the X axis values and byte value in a given position providing the Y values. You can select a window of packets to display at once (defaults to 30) to see patterns over time. If packet headers are more interesting than payload, there is an option to expand the proportion of space taken by header data so it's easier to see. There are also options to pause the animation, move fwd and back one packet at a time, and jump to specific packts. Finally, if you want to look at the base data for a given packet, you can display the packet in hex.
Right now, I've found there's a rough top limit of 3000 packets, but it really depends on your machine.