Macro Flash Adaptor

Recently I made a post in the WTB section for a flash adaptor for the Olympus XA4. The XA4 is a 35mm compact with f3.5 28mm lens, and it focuses as close as twelve inches. I didn't get a response, and I didn't really expect to. The camera iself is pretty rare, and the flash adaptor is even harder to come by. It is pictured and described here:
http://www.flickr.com/groups/olympusxa/discuss/72157623461621606/

I think my chances of finding one are pretty slim. However, looking at the thing, it doesn't seem to be much more than a diffuser and a mirror on a hinge. How hard would it be build something like this? What would I need to consider?

Not to be a complete idiot or anything, but why would you want to use a viewfinder camera for shooting closeup? The days of focusing frames for, e.g., Kodak Instamatics, are long gone.

When shooting closeup there's really no substitute for a camera that allows focusing and composing through the lens. For mobile subjects, including flowers that blow in the wind, an SLR is ideal. A view camera will work for static subjects.

Shooting closeup is challenging enough that there's no reason to hobble yourself with unsuitable equipment.

Two reasons: The XA4 is pocketable, and I already get good results. I take it out on my lunch hour and often visit (some might say) dubious areas. My subjects are walls, signs, poles, litter, etc. I won't be lugging a view camera or even an SLR around. But it's not a hindrance. On the XA4 I dial the focus all the way down to 1 (foot) and use the camera's wrist strap to measure distance. Dead on. And easy to correct for parallax.


Anyway, I'm looking to use the flash for the same type of shooting but in low light, at night, in winter...