Thank you. I've watched the screencast but I really do fail to see any utility in Xiki, only novelty. Can you describe something that Xiki can do that cannot be done with `:r!`? I would really love to add Xiki to my toolbox if it is useful, but I fail to see that.
If you want something better than :r! in vim, use emacs as a shell. I used emacs as a shell for years - you can cut-n-paste (multiple buffers), use the mouse to mark regions, save the entire session as a file, load a previously used session, search back, search forward, edit previous commands before running them, edit the output of previous commands (and then run them), execute the odd elisp expression (need a calculator quickly? It's built in), surf the web, read/send email, read usenet (or read slashdot), play rogue, elisa, snake or tetris, annotate previous commands, run multiple shells.
You still get all the normal stuff too - autocomplete, file and directory browsing, standard piping to forked processes, set/reset/unset variables, syntax highlighting of your shell, normal edit-compile-debug cycle, etc
(I've heard rumours that there's a text editor included with it too ;-)