Very cool project. It would be even cooler if you could actually send 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.
The complete Python based graphical scripting environment with import/edit of Pcap files and other goodies beta is scheduled for release in mid-to-end of July. If you want to be a beta tester, follow @wirefloss on twitter.
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 in concert (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!