I like the idea of a shell that uses proportionally spaced fonts instead of monospaced fonts.
It only needs to implement some type of simple layout language - implemented in XML, and similar to XHTML, whilst styling would be done with CSS to achieve a consistent output regardless of applications (i.e., all tables would look the same). I doubt the implementation would take long, although changing all the applications to output in the new format would be a hassle - I'd imagine that a shell like this would add a new switch by default to all executed commands to tell them to output formatted text instead of plain text.
It is just that there are too many other, more important, things to do than something like that!
Regarding the original screenshot - it looks nice but is a little too fancy - any chance of posting an image without the textured backdrops (i.e., plain, like a default configuration). I also do not like the scrollbars - too much darkness in them. I like the tree view though. I prefer the OS4 window borders to your window borders. The tab looks funny, as if it isn't attached to the content it is attached to.
