Here are some Epiphany extensions that I have written. Copy the .py and the .ephy-extension files in pairs to your ~/.gnome2/epiphany/extensions folder, then turn them on from the Extension Manager in the Tools menu.
This one has some behavior issues, but (sometimes) does the job I needed. If you fix the broken back-button issue, please let me know.
Reworked to apply to pasting to the location bar; this seems to work a lot better:
I liked the main part of Stefan Stuhr's Only One Close Button, but decided I preferred having a close button on the active tab. Turns out Christian Persch had already written this, but it doesn't work well with Stefan's extension. Here I have split it up so you can enable or disable pieces as you wish. Be aware that some of these conflict, and may do odd things if enabled together.