The basic problem with Run Command (Alt+F2) is that it can not take "sudo" commands; sudo requires a followup query to input a password. About 95% of the commands I use in terminal require a password, such as adding ppa's or installing software from a script. Thus, the alt shortcut is 95% of the time useless.
In my search for a solution, no lens appears to exist. I found two mockups of what this would look like. The one at this link is the nicer of the two:
In an answer to his query, "Teester" said this: "There is currently nothing that does exactly what it pictured above since, at the moment, a lens cannot define a content area like the one pictured in order to display (and update) the output of a command. "
The other mockup was given as a solution to another brainstorm idea (http://brainstorm.ubuntu.com/idea/28565/).
That idea was resolved, however did not address the issue I am bringing forth. Anyways, here is his mockup:
Disregard the "Alt or " in the title. I learned something new today, mainly, that the Alt button is program specific.