It looks like the underlying problem is:

$ sudo apt-get install qemu-system-x86
[...]
The following packages have unmet dependencies:
qemu-system-x86 : Depends: seabios (>= 1.7.2-2~) but it is not going to be installed

I imported seabios 1.7.3-3~bpo70+1 from wheezy-backports and this should hopefully fix this problem.

There was a supplementary issue on top of the missing seabios (bad breaks field in qemu-kvm). I fixed that and at the same time synced with the official wheezy-backports of the package. Will be fixed in qemu-kvm 1.7.0+dfsg-2~kali2.

Just uploaded qemu_1.7.0+dfsg-2~kali2.dsc to kali-proposed-updates.

Thanks rhertzog. But, do I need to wait until kali 1.0.7 will be released??

According to my /etc/debian_version file, my host is 1.0.6 but if I try to install qemu-system-x86 package, the following errors appears:

root@britannia:~# cat /etc/debian_version
Kali Linux 1.0.6
root@britannia:~# apt-get install qemu-system-x86
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
augeas-lenses dnsmasq-base ebtables iptables libart-2.0-2 libaugeas0 libbonoboui2-0 libbonoboui2-common libgail18 libglade2-0 libgnomecanvas2-0 libgnomecanvas2-common libgnomeui-0
libgnomeui-common libgtk-vnc-1.0-0 libgtk-vnc-2.0-0 libgvnc-1.0-0 libnetcf1 libnetfilter-conntrack3 libnfnetlink0 libnl1 libnuma1 libpcap0.8 libspice-client-glib-2.0-1
libspice-client-gtk-2.0-1 libusbredirhost1 libusbredirparser0 libxml2-utils lvm2 python-gconf python-glade2 python-gnome2 python-gtk-vnc python-ipy python-libxml2 python-pyorbit
python-spice-client-gtk python-urlgrabber
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
ipxe-qemu libbrlapi0.5 libfdt1 libvdeplug2 libxen-4.1 qemu-keymaps qemu-system-common seabios
Suggested packages:
samba vde2 sgabios
The following packages will be REMOVED:
libvirt-bin libvirt0 python-libvirt virt-manager virt-viewer virtinst
The following NEW packages will be installed:
ipxe-qemu libbrlapi0.5 libfdt1 libvdeplug2 libxen-4.1 qemu-keymaps qemu-system-common qemu-system-x86 seabios
0 upgraded, 9 newly installed, 6 to remove and 0 not upgraded.
Need to get 4,867 kB of archives.
After this operation, 4,551 kB disk space will be freed.
Do you want to continue [Y/n]?

Why apt needs to remove all libvirtd packages and dependencies?

Argh, I see that:

• qemu-system-x86 break libvirt0 << 1.0, because older versions
  didn't work with qemu 1.3+ correctly

So that's the issue. I just imported libvirt from wheezy-backports as well.

Anyway, you don't have to wait until kali 1.0.7 will be released, the packages will be moved in the main repository way before. In the mean time you can add the kali-proposed-updates repository in /etc/apt/sources.list.

Thanks rhertzog. qemu-system-x86 installs ok now, but not libvirt-bin to manage this host:

root@britannia:~# apt-get install libvirt-bin
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libvirt-bin : Depends: init-system-helpers (>= 1.11~) but it is not installable
Recommends: dnsmasq-base (>= 2.46-1) but it is not going to be installed
Recommends: qemu-kvm but it is not going to be installed or
qemu (>= 0.9.1) but it is not going to be installed
Recommends: libxml2-utils but it is not going to be installed
Recommends: ebtables but it is not going to be installed
Recommends: parted but it is not going to be installed
E: Unable to correct problems, you have held broken packages

virt-manager installs ok with all dependencies.

Sorry to disturb another time with this, but exists some solution to install libvirt-bin in kali 1.0.6?? virt-manager and qemu installs and works without problems.

Thanks for the notice. I just imported init-system-helpers from wheezy-backports. It should work now.