Is that even possible? Can NPCs drop bound weapons when the PC can't?
You can create a 'permabound' item via glitch on PS3/Xbox, or PC without UOP. If you are on PC with UOP, you can simply command console in a permabound item. When I command console in a permabound item, it is not droppable until I also command console its status to 'nonquest item'.
Since permabound items can be rendered droppable and weigh zero, they can be reverse pick pocketed. Since OP has already sorted out how to reverse pickpocket a bound claymore to his fan, I'm sure he is using a permabound weapon.
More info: http://www.uesp.net/wiki/Oblivion:Glitches#Permanent_Bound_Items