Nice shot MA. You probably wouldn't know it was HDR unless you pointed it out.
Is most of the motion blur caused by the +EV frame, or do the multiple frames contribute noticeably?
One I was time trying to takes some motion blurred water shots, but not able to extend the shutter time enough. Later I had the idea of doing multiple frames(on a tripod but without changing EV) and merging them. I have never tried it though, but I figure you will see movement in the water, but everything else would stay crisp.