(Yes, sounds like Professor Fansworth's Smelloscope.... sadly.)
This guy is one of a few conversions I did a while ago that never got posted here. Each got to about 80% completion before I ADD'd off to the next idea. The arms are the gunner arms from the Adeptus Mechanicus tank crew member found on every Space Marine vehicle sprue... you know, the guy nobody seems to use? Yeah, that one. His hands are flat enough on top to press them together in a reasonable facsimile of a two handed grip. I drilled through them and placed a thin rod so that they would keep their orientation, then pinned the blade and the pommel (?) to the extending ends of the rod. The arms will not fit completely flush at the shoulder when the hands are together, but a little putty and the comically huge shoulder pads will completely obscure that. The blade is the Black Reach captain's blade.
At roughly the same time frame I did this fellow, meant to be a Chapter Master.
I was getting all fancy with the magnets, so I gave him a bolter, bolt pistol or plasma pistol. He's a converted Black Reach captain with a regular marine chest plate in place of the rather unique one that the model normally uses. The cloth covering his bits there hides the fact that his legs just sort of terminate into nothingness. There are no bits to cover. It's not really visible unless you turn the model completely upside down. The little crest on the helmet is green stuff.
Everybody has their little rock to stand on too. It's standard issue once you reach a certain rank.