I received my Lord Celestant mounted yesterday and I just had to put him together and convert him. Below is my work so far, chaos bits again used like in my Knights of Old Caliban conversions, but also a mortarch head swapped on to the mount and I've tried to cyber it up a bit with leg mechanics a power tube on his face as well as a cabled tail with a chain sword at the end. He's equipped with a power fist and either a relic blade or a paragon blade. I also plan to mount a storm shield on the side of the saddle so it looks like he could just un-holster it.
Thoughts always welcome :)