Installing ubuntu-desktop on top of Kubuntu Quantal

I know that in general it might not be such a good idea to mix desktop environments. However I like both KDE and Unity and don't mind some extra applications. So I'm willing too accept the extra menu clutter in KDE. But there are a few concerns:

1. Both Kubuntu and Ubuntu use LightDM, should I expect some problems there? Which LightDM theme will be used by default?
2. Should I expect problems with some of the KDE services like Nepomuk and Akonadi when starting a Unity session?
3. Am I overlooking things, are there other known issues with this sort of setup?

Anyone of you who has both KDE and Unity installed and what are your experiences?

*bump*

Ok, I just did it. Well not entirely happy but it could've be worse :P

Starting from a pure Kubuntu I installed:
ubuntu-desktop
xubuntu-desktop
gnome-shell

The LightDM theme remains that of Kubuntu.

Ubuntu
Receive 'internal error' message after each start. Non-Gnome applications like Firefox and Thunderbird have KDE's color theming. Outside that Unity appears fine. The lack of an application menu is a pro here as you don't notice the 'clutter' from other DEs.

Xubuntu
Complete mess. lots of icons on the desktop (mounted drives appear twice). Also KDE-colors in 'neutral' applications. Window borders have gone so Xubuntu-session is unusable. Same error message as Ubuntu session.

Gnome-Shell
Quite similar to Unity. Error message is handled nicely by Gnome Shell (less intrusive) and theming is also the same. Ambiance theme for Gnome-applications, KDE colors for other apps.

Kubuntu
Largely unaffected. No error message and the only problem is, as expected, menu clutter.

One other weird thing (or maybe not) is that the splash screen now says "Xubuntu 12.10".