Very cool project. It would be even cooler if you could actually <i>send</i> your hand-crafted packets to a modifiable host/IP once you're done. To test if the user actually succeeded in creating a valid packet.
Great tool.<p>A clear text output box would be fine (since there are a few text based protocol which could be handled more easily if we would have clear text instead of hex).
Say u have a single packet Pcap, with a multi-layer binary encoded packet. Click the button, get a complete editable stack graph pre-populated with values from the packet. Edit layers <i>in concert</i> (no annoying Copy/Paste between layers as in wirefloss.com). When done, click and auto-generate a Python code stub sending the new packet to a wire. Coming soon!