Uwe Heuer has successfully implemented vectored thrust on his Ho 229 model. It only works in the yaw dimension but is effective in controlling the adverse effects of the exhaust seen in all Ho 229 EDF models.
From: "Uwe G. Heuer"
I do not know whether you noticed it, I have found a way to do away with the thrust-tubes on the Ho IX V3 EDF-models. It is a thrust-rudder that works without gyroscope, it is controlled together with the aileron: See article. A small fin is still needed. I have tried to fly without it, but with a very small fin it was not possible to give full thrust. My small model side-slipped in straight and level flight. I think a little fin at the bottom of the rump is better than big thrust-tubes at the top of this pretty flying wing. In the video, you can not see the improvised thrust rudders. Now they are integrated into the cell and I am still testing the optimal settings for the coupling of aileron and thrust rudder, but then my small IX built in 2004 had done her job like the space shuttle these days ;-)...and i'll fly this model yet...so no more experiments with it.