Web Developer tools in Midori web browser
For the version currently included in the Ubuntu Repos (0.4.7)
I was unable to find the shortcut to open the Web-Dev tools, but going to the menu (the cog-like button on the right) and click inspect page. Then it will open a window, which is exactly like chrome/chromium's one (DOH, ITS WEBKIT-BASED!).
Hope this helps someone who is looking on the net for something similar to this.
For the newer version (0.5.7):
Ctrl+Shift+I - Which is the default in chrome(and I think in FF)
NOTE: The versions mentioned above are up to date for the current date.
You might try this solution: https://getfirebug.com/firebuglite. This will allow you to add the lite version through a javascript tag include.