I imagine the underlying cause is not necessarily ubuntu-system-settings's alone (or at all), but it does not currently cross-build under utopic.
See the attached sbuild log, but the interesting part is:
The following packages have unmet dependencies:
libaccountsservice-dev:armhf : Depends: gir1.2-accountsservice-1.0:armhf (= 0.6.35-0ubuntu7)
Depends: libaccountsservice0:armhf (= 0.6.35-0ubuntu7) but it is not going to be installed
Depends: libpolkit-gobject-1-dev:armhf but it is not going to be installed
libnm-glib-dev:armhf : Depends: libnm-glib4:armhf (= 0.9.8.8-0ubuntu9) but it is not going to be installed
Depends: gir1.2-networkmanager-1.0:armhf (= 0.9.8.8-0ubuntu9) but it is not going to be installed
Depends: libnm-util-dev:armhf but it is not going to be installed
libqmenumodel-dev:armhf : Depends: libqmenumodel0:armhf (= 0.2.7+14.04.20140305-0ubuntu2) but it is not going to be installed
libubuntu-download-manager-client-dev:armhf : Depends: libudm-common-dev:armhf (= 0.3+14.10.20140430.1-0ubuntu1) but it is not going to be installed
Depends: libubuntu-download-manager-common-dev:armhf (= 0.3+14.10.20140430.1-0ubuntu1) but it is not going to be installed
Depends: qtbase5-dev:armhf but it is not going to be installed
libubuntuoneauth-2.0-dev:armhf : Depends: libsignon-qt5-dev:armhf but it is not going to be installed
Depends: qtbase5-dev:armhf but it is not going to be installed
libunity-mir-dev:armhf : Depends: libunity-mir1:armhf (= 0.4+14.10.20140430.3-0ubuntu1) but it is not going to be installed
Depends: libmirserver-dev:armhf (>= 0.1.8) but it is not going to be installed
Depends: libplatform-api1-dev:armhf but it is not going to be installed
Depends: qtbase5-dev:armhf but it is not going to be installed
qt5-default:armhf : Depends: qtbase5-dev:armhf but it is not going to be installed
qtbase5-private-dev:armhf : Depends: qtbase5-dev:armhf (= 5.2.1+dfsg-1ubuntu15) but it is not going to be installed
qtdeclarative5-dev:armhf : Depends: libqt5quick5:armhf (= 5.2.1-5ubuntu1) but it is not going to be installed or
libqt5quick5-gles:armhf but it is not installable
Depends: libqt5quickparticles5:armhf (= 5.2.1-5ubuntu1) but it is not going to be installed or
libqt5quickparticles5-gles:armhf but it is not installable
Depends: libqt5quicktest5:armhf (= 5.2.1-5ubuntu1) but it is not going to be installed
Depends: qtbase5-dev:armhf but it is not going to be installed
ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: ubuntu-system-settings 0.1+14.10.20140428-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
NonfreeKernelModules: wl nvidia
ApportVersion: 2.14.2-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Tue May 6 17:47:16 2014
SourcePackage: ubuntu-system-settings
UpgradeStatus: No upgrade log present (probably fresh install)
I started to look into why this stopped working (it requires fairly regular attention due to churn in the archive), will continue to fix issues this week.