I have done an impromtu light modifer once using my speedotron blackline 7" specilar reflector, with the flash bulb in a folding fan flash bulb holder that did not have th fan unfurled.
Down side was the challenge of mounting it. I gaff taped the reflector it to a boom arm to manouver the thing, and laos taped a cold shoe off camera flash bracket to support the folding fan flash holder.
The shot looked pretty good.. Kind of half way between profoto/speedo flash with bare bulb and with specular reflector.
Used a hand held folding fabric diffuse silver panel held by an assistant to provide the fill lighting, just out of image range.
Shot was for a portrait in an old flour mill that had no power, and I had no urge to haul a generator for the freebe shoot.
Lugging the boom stand was pain enough. The room needed the power that flash bulbs, a sitter that stayed still and a 1/30" shutter speed to fill the room with just the right amount for the passive the background lighting.
The room was big enough my 4-aa on camera, or even the Metz CT60 was not quite up to the task. One M3 bulb sure was though.
Used flash bulb