[Xperia Z Themes and Apps] Sichroteph:
OP, here is the status bar xml that worked with my 4.2.2 rom to center the clock :

<?xml version="1.0" encoding="utf-8"?>

<com.android.systemui.statusbar.phone.PhoneStatusBarView android:orientation="vertical" android:id="@id/status_bar" android:background="@color/system_ui_opaque_background" android:focusable="true" android:fitsSystemWindows="true" android:descendantFocusability="afterDescendants"

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:systemui="http://schemas.android.com/apk/res/com.android.systemui">

<com.android.systemui.statusbar.policy.Clock android:textAppearance="@style/TextAppearance.StatusBar.Clock" android:gravity="center" android:id="@id/clock" android:layout_width="fill_parent" android:layout_height="fill_parent" android:singleLine="true" android:paddingStart="0.0dip" />

<ImageView android:id="@id/notification_lights_out" android:paddingBottom="2.0dip" android:visibility="gone" android:layout_width="@dimen/status_bar_icon_size" android:layout_height="fill_parent" android:src="@drawable/ic_sysbar_lights_out_dot_small" android:scaleType="center" android:paddingStart="6.0dip" />

<com.sonymobile.systemui.statusbar.operator.OperatorLabel android:textAppearance="@style/TextAppearance.StatusBar.Clock" android:ellipsize="marquee" android:gravity="start|center" android:id="@id/operator" android:visibility="gone" android:layout_width="wrap_content" android:layout_height="fill_parent" android:singleLine="true" android:paddingStart="6.0dip" android:paddingEnd="4.0dip" />

<LinearLayout android:orientation="horizontal" android:id="@id/status_bar_contents" android:layout_width="fill_parent" android:layout_height="fill_parent" android:paddingStart="6.0dip" android:paddingEnd="6.0dip">

<com.android.systemui.statusbar.StatusBarIconView android:id="@id/moreIcon" android:visibility="gone" android:layout_width="@dimen/status_bar_icon_size" android:layout_height="fill_parent" android:src="@drawable/stat_notify_more" />

<com.android.systemui.statusbar.phone.IconPartitioner android:id="@id/notification_icon_area" android:layout_width="0.0dip" android:layout_height="fill_parent" android:layout_weight="1.0">

<com.android.systemui.statusbar.phone.IconMerger android:gravity="center_vertical" android:orientation="horizontal" android:id="@id/notificationIcons" android:layout_width="wrap_content" android:layout_height="fill_parent" />

<LinearLayout android:orientation="horizontal" android:id="@id/system_icon_area" android:layout_width="wrap_content" android:layout_height="fill_parent">

<LinearLayout android:gravity="center_vertical" android:orientation="horizontal" android:id="@id/statusIcons" android:layout_width="wrap_content" android:layout_height="fill_parent" />

</LinearLayout>

</com.android.systemui.statusbar.phone.IconPartitioner>

<LinearLayout android:gravity="center" android:orientation="horizontal" android:id="@id/signal_battery_cluster" android:layout_width="wrap_content" android:layout_height="fill_parent" android:paddingStart="2.0dip">

<include android:id="@id/signal_cluster" android:layout_width="wrap_content" android:layout_height="wrap_content" layout="@layout/signal_cluster_view" />

<TextView android:layout_gravity="start|center" android:id="@id/battery_text" android:visibility="gone" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/status_bar_settings_settings_button" android:singleLine="true" android:paddingStart="4.0dip" style="@style/SystemBarNotificationText" />

<ImageView android:id="@id/battery" android:layout_width="wrap_content" android:layout_height="wrap_content" android:paddingStart="4.0dip" />

</LinearLayout>

</LinearLayout>

<LinearLayout android:orientation="horizontal" android:id="@id/ticker" android:background="@color/system_ui_opaque_background" android:animationCache="false" android:layout_width="fill_parent" android:layout_height="fill_parent" android:paddingStart="6.0dip">

<ImageSwitcher android:id="@id/tickerIcon" android:layout_width="@dimen/status_bar_icon_size" android:layout_height="@dimen/status_bar_icon_size" android:layout_marginEnd="4.0dip">

<com.android.systemui.statusbar.AnimatedImageView android:layout_width="@dimen/status_bar_icon_size" android:layout_height="@dimen/status_bar_icon_size" android:scaleType="center" />

<com.android.systemui.statusbar.AnimatedImageView android:layout_width="@dimen/status_bar_icon_size" android:layout_height="@dimen/status_bar_icon_size" android:scaleType="center" />

</ImageSwitcher>

<com.android.systemui.statusbar.phone.TickerView android:id="@id/tickerText" android:paddingTop="2.0dip" android:layout_width="0.0dip" android:layout_height="wrap_content" android:layout_weight="1.0" android:paddingEnd="10.0dip">

<TextView android:textAppearance="@style/TextAppearance.StatusBar.PhoneTicker" android:layout_width="fill_parent" android:layout_height="wrap_content" android:singleLine="true" android:textAlignment="viewStart" />

<TextView android:textAppearance="@style/TextAppearance.StatusBar.PhoneTicker" android:layout_width="fill_parent" android:layout_height="wrap_content" android:singleLine="true" android:textAlignment="viewStart" />

</com.android.systemui.statusbar.phone.TickerView>

</LinearLayout>

</com.android.systemui.statusbar.phone.PhoneStatusBarView>

Here is the systemUI.apk for those that had black status bar before. I didn't found time to make a flashable zip.

Please try and report !