If you have an extra $20 to spare (or if you can find it cheaper elsewhere, but ebay prices were running aroundd the same with shipping last I check) go with the Typhus model. If not, model it yourself if you can make it look good to your satisfaction (i currently tried converting bolters to noise marine sonic blasters but they look horrible so as much as I hate to do it, I'll be forking over the money for the actual bits). Just to clarify something, I'm assuming you're modeling a manreaper for the plaguebringer weapon correct? Because the only one that actually carries the manreaper is typhus himself.
"There is a cancer eating at the Imperium. With each decade it advances deeper, leaving drained, dead worlds in its wake. This horror, this abomination, has though and purpose which functions on an unimaginable, galactic scale and all we can do is try to stop the swarms of bio-engineered monsters it unleashes upon us by instinct. We have given the horror a name to salve our fears; we call it the Tyranid race, but if it is aware of us at all, it must know us only as Prey."