Wubi was about to get scrapped a couple of weeks ago, but some developers are still working on it. It seems that it might be released alongside Ubuntu 13.04 after all.
Wubi or Windows-based Ubuntu Installer has garnered quite a lot of bugs over time, and there was no one left to fix or maintain it. Canonical was about to ditch it entirely, but a few developers have managed to repair some of the major problems.
“I have merge all of your fixes, tested it with window7 and they work correctly. For 13.04 we have disabled and stopped building disk-images, so those are gone. And the isolist.ini is correct as per your patches to match reality,” stated Canonical's Dmitrijs Ledkovs, in response to a few fixes sent by a another developer.
As it stands right now, Wubi is only confronted with a UEFI related issue, but it might get fixed just in time for Ubuntu 13.04.