With the help of Alez Zeimet (AFOL1969) and Strikeman, I've created full building instructions for the SBrick-version of the Ultimate 8043 Motorized excavator. Go to the instructions-page to get them.
It wasn't just a matter of exchanging the Power-functions with SBricks. Because of the different shape of the SBricks and the fact that there are 4 PF-connectors on top, the SBricks didn't fit. So I rebuilt the U-8043 and modified it so that 2 SBricks would fit neatly inside the model. And the profile I created for the Link Belt 250 X 3 excavator worked perfectly with this model as well.