Hi,
Yes you might be able to just replace your systemui.apk with one with my patch applied, though I can't guarantee that it will work and its definitely better to rebuild the whole system image yourself from source.
Also my patch at this stage only provides toggling the display of the systembar via a broadcast intent, so unless you are able to use adb or some other means to get to a commandline in order to use the "am" cmd you would not be able to re-display the systembar without rebooting.
I wonder if there is any interest in integrating this patch into the android x86 git repos? of course with added functionality to toggle the setting via perhaps the power-menu the way it is done in CM and AOKP?
If so I'd be happy to submit a patch.
Maks.