[Sony Xperia S, Acro S, Ion] Till-Kruspe:
It simple really...

decompile your settings.apk...then go to res/xml folder...edit this file device_info_settings.xml and add this line:

<Preference android:title="@string/[COLOR="Red"]XXXXX[/COLOR]_heading" android:key="[COLOR="red"]XXXXX[/COLOR]_heading" android:summary="@string/[COLOR="red"]XXXXX[/COLOR]_version" style="?android:preferenceInformationStyle" />

Edit the XXXXX to your like...

This is mine setup:

</PreferenceScreen>
<Preference android:title="@string/model_number" android:key="device_model" android:summary="@string/device_info_default" style="?android:preferenceInformationStyle" />
<Preference android:title="@string/firmware_version" android:key="firmware_version" android:summary="@string/device_info_default" style="?android:preferenceInformationStyle" />
[COLOR="Red"]<Preference android:title="@string/android_heading" android:key="android_heading" android:summary="@string/android_version" style="?android:preferenceInformationStyle" />[/COLOR]
<Preference android:title="@string/baseband_version" android:key="baseband_version" android:summary="@string/device_info_default" style="?android:preferenceInformationStyle" />
<Preference android:title="@string/kernel_version" android:key="kernel_version" android:summary="@string/device_info_default" style="?android:preferenceInformationStyle" />
[COLOR="red"] <Preference android:title="@string/engine_heading" android:key="engine_heading" android:summary="@string/engine_version" style="?android:preferenceInformationStyle" />
<Preference android:title="@string/cpu_heading" android:key="cpu_heading" android:summary="@string/cpu_version" style="?android:preferenceInformationStyle" />
<Preference android:title="@string/version_heading" android:key="version_heading" android:summary="@string/ziewing_version" style="?android:preferenceInformationStyle" />
<Preference android:title="@string/date_heading" android:key="date_heading" android:summary="@string/build_date" style="?android:preferenceInformationStyle" />[/COLOR]
<Preference android:title="@string/build_number" android:key="build_number" android:summary="@string/device_info_default" style="?android:preferenceInformationStyle" />
[COLOR="red"]<Preference android:title="@string/developer_heading" android:key="developer_heading" android:summary="@string/developer_version" style="?android:preferenceInformationStyle" />[/COLOR]
</PreferenceScreen>

The red are mine custom info...

Now go to value folder and edit strings.xml

put this at the bottom of the line:

<string name="[COLOR="Red"]XXXXX[/COLOR]_heading">[COLOR="red"]XXXXX[/COLOR]</string>
<string name="[COLOR="red"]XXXXX[/COLOR]_version">[COLOR="Red"]XXXXX[/COLOR]</string>

Mine setup:

<string name="version_heading">ZieWing™ version</string>
<string name="ziewing_version">v3.2 beta-1 coconut</string>
<string name="date_heading">Build date</string>
<string name="build_date">Tue Feb 12 02:36 PST 2013</string>
<string name="cpu_heading">CPU</string>
<string name="cpu_version">ARMv7 Processor rev 2 (v7l)</string>
<string name="android_heading">Codename</string>
<string name="android_version">Ice Cream Sandwich (ICS)</string>
<string name="engine_heading">Engine version</string>
<string name="engine_version">X-CORE™ alpha v1</string>
<string name="developer_heading">Developer</string>
<string name="developer_version">Till-Kruspe@xda</string>

After your satisfied editing it to your like...recompile it and your done...

Hope you understand it... ;)