I believe LVM is probably what Kurotenshi is looking for.
If I remember correctly there is an guided LVM option on the Live CD however I think there are several problems with this:
1) (Blurry on this) I believe there is no option to keep any existing installs with LVM (might of course be wrong).
2) For the new user there is not much information available on LVM, they simply won't know what it is. I started using Ubuntu over a year ago and have just now started using LVM.
3) LVM is probably too difficult of a concept for the new user, especially first timers.
4) Even if the user sets up guided LVM how do they manipulate it. As far as I know there are no graphical tools for manipulation of LVM installed by default in Ubuntu.
Therefore, what I propose is a two part application to help new users/users with less IT skills to install LVM by default.
The first part would be on the Live CD, say an option allowing users to do a "dynamic install" (no sense in throwing jargon like LVM at people who don't understand it) which will install LVM alongside existing partitions for other OSes.
The second part would be a graphical tool for the manipulation of the "dynamic install" installed by default in Ubuntu.
LVM is a great tool and new users really need more exposure to it.