Short story: I bought one; it works fine; here's an illustration of one application that's interesting to me.
First, here is the promised fly, as whole frame reduced to 1024 wide.

Then, a crop of original pixels reduced to 50%.

Finally, here is the setup. Yes it is kind of minimal, and that's the point.

This is a combination of stuff that I haven't plugged together before:
. Canon T1i camera (APS-C, 4752x3168 = 15 megapixels)
. Canon 18-55mm AF IS kit lens, reversed
. Meike MK-C-UP adapter to electronically couple the camera to the reversed lens ($52.95 with free shipping at http://www.amazon.com/gp/product/B00LJRD8PW).
. DSLR Controller app running in Android tablet with hardwired USB to camera
. mechanical support and light
Focus stacking was done by having the DSLR Controller app drive the focus motor of the reversed kit lens, 24 frames at 0.5 seconds and nominal f/7.1, spaced by one middle-size step. Zoom setting around 30 mm.
I don't know whether this will interest anybody else, but since I had to do something to make sure the adapter was OK, I thought I'd post it out. I also don't know exactly what the fly is. It was an oddly hairy beast that turned up between my window and the outside screen a couple of days ago.
--Rik