I'm getting the same problem.  I've got standard kubuntu 10.10 installed.  After adding the beta ppa, I get the following when trying to upgrade to 4.6RC:
[code]
matt@matt-desktop:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages have been kept back:
  akonadi-server akregator amarok amarok-common amarok-utils ark digikam digikam-data dolphin
  dragonplayer gwenview k3b k3b-data kaddressbook kate kde-window-manager kde-zeroconf kdebase-bin
  kdebase-data kdebase-runtime kdebase-workspace kdebase-workspace-bin kdebase-workspace-data
  kdebase-workspace-dev kdebase-workspace-kgreet-plugins kdegraphics-strigi-plugins kdelibs-bin kdelibs5
  kdelibs5-data kdelibs5-dev kdelibs5-plugins kdemultimedia-kio-plugins kdepasswd kdepim-groupware
  kdepim-kresources kdepim-runtime kdepim-strigi-plugins kdepim-wizards kdepimlibs-kio-plugins kdm
  kdoctools kfind khelpcenter4 kinfocenter klipper kmail kmix kmousetool knotes konqueror
  konqueror-nsplugins konsole kontact kopete korganizer kppp krdc krfb ksnapshot ksysguard ksysguardd
  ktimetracker libakonadi-contact4 libakonadi-kcal4 libakonadi-kde4 libakonadi-kmime4 libk3b6
  libk3b6-extracodecs libkabc4 libkatepartinterfaces4 libkblog4 libkcal4 libkcddb4 libkde3support4
  libkdecorations4 libkdecore5 libkdepim4 libkdesu5 libkdeui5 libkdewebkit5 libkdnssd4 libkfile4
  libkholidays4 libkhtml5 libkimap4 libkimproxy4 libkio5 libkjsapi4 libkjsembed4 libkldap4 libkleo4
  libkmediaplayer4 libkmime4 libknewstuff2-4 libknewstuff3-4 libknotifyconfig4 libkntlm4
  libkonqsidebarplugin4a libkontactinterface4 libkopete4 libkparts4 libkpgp4 libkpimidentities4
  libkpimtextedit4 libkpimutils4 libkpty4 libkresources4 libkrosscore4 libkrossui4 libkscreensaver5
  libksgrd4 libksieve4 libksignalplotter4 libktexteditor4 libktnef4 libkunitconversion4 libkutils4
  libkwineffects1a libkworkspace4 libkxmlrpcclient4 liblsofui4 libmailtransport4 libmessagecore4
  libmessagelist4 libmicroblog4 libmimelib4 libnepomuk4 libnepomukquery4a libokularcore1 libphonon-dev
  libphonon4 libplasma-geolocation-interface4 libplasma3 libplasmaclock4b libplasmagenericshell4
  libprocessui4a libqapt-runtime libsolid4 libsolidcontrol4a libsyndication4 libthreadweaver4
  marble-plugins okular okular-extra-backends phonon phonon-backend-xine plasma-dataengines-addons
  plasma-dataengines-workspace plasma-desktop plasma-netbook plasma-scriptengine-javascript
  plasma-widget-folderview plasma-widget-kimpanel plasma-widget-quickaccess plasma-widgets-addons
  plasma-widgets-workspace polkit-kde-1 python-kde4 systemsettings
The following packages will be upgraded:
  kamera kcalc kde-l10n-engb kdebase-runtime-data kdegraphics-libs-data kmag kopete-gcall krosspython
  ksystemlog kwalletmanager libakonadi-kabc4 libattica0 libgpg-error0 libgpgme++2 libkonq5-templates
  libksane0 libpolkit-agent-1-0 libpolkit-backend-1-0 libpolkit-gobject-1-0 libpolkit-qt-1-0 libqapt1
  libqgpgme1 libqjson0 libsoprano-dev libsoprano4 marble-data oxygen-icon-theme
  oxygen-icon-theme-complete plasma-scriptengine-python plasma-widget-kimpanel-backend-ibus policykit-1
  policykit-1-gnome printer-applet python-qt4 python-qt4-dbus python-sip qapt-batch soprano-daemon
  system-config-printer-kde
39 upgraded, 0 newly installed, 0 to remove and 159 not upgraded.
Need to get 57.1MB of archives.
After this operation, 13.6MB of additional disk space will be used.
Do you want to continue [Y/n]? 
[/code]

This doesn't seem to be right.  There seems to be some serious dependency issues in these packages.