Lea: The Unity design process (and how you can play a part in it)

>Not really. There are some similarities with PowerShell, but (to me, at least) PowerShell doesn't go nearly far enough. From what I can see, it's just a REP loop front-end for the .Net framework, with some shell functionality worked in.

And very powerful introspection capabilities.

>As an example, I don't believe you can use PowerShell to create widgets that sit inline in the terminal. It's .Net, so you can presumably create windows with things in them, but you can't (for example) create a scrollable list or a progress bar inline in the terminal text.

You can, by working with the terminal directly. But it'll be more like ncurses programs.

>I don't believe PowerShell has screen-like functionality, though I could be wrong.

I've seen utility which allows to detach and attach to a running PowerShell server. Essentially, the 'screen' utility but with some missing functionality.

>As far as I know, PowerShell has no equivalent to the named buffers scheme I'm proposing, beyond possibly being able to hamfist it through global variables.
?

>As far as I've seen, PowerShell is still expecting to run on a terminal running a monospaced font, and has no way of breaking out of that mode.
Not really, posh can be run just fine in complex GUI. It's mostly output-agnostic.