From what I understood, x86 target is supposed to work for pretty everything (that doesn't play with low level stuff) and is aimed at UI/Integration testing with the help of an IDE on your PC.
Armel qemu support is not sufficient (?) for running armel GUI apps on your PC. It's only good for building and sending to the device.
For specific d-bus handling I don't know. D-bus by itself could work but everything around, I'm not sure.