Does terminal have quickedit mode?

There is already something equivalent to this: by highlighting any text (not just in the terminal, but in almost any application), that text is put into the xclipboard. You can paste it by clicking the middle mouse button. If you're using a touchpad with no middle button, Ubuntu should allow you to click both buttons simultaneously to simulate a middle mouse click.

This is distinct from the ctrl+c/ctrl+v clipboard you are probably used to.

Like in text editor, you can make selection in terminal using the cursor. But to copy/paste from/to the terminal you'll have to use Ctrl + Shift + C and Ctrl + Shift + V respectively.

I recommend you install guake terminal (sudo apt-get install guake). It's great for usage and has many pretty features. Try it.