Not much more to it than what you see in those pics. The plastic backpack is poached from a Scubapro Knighthawk, as is the plastic tank mounting plate (which you cannot see) and the Supercinch cam band. So, the backpack and tank mounting system is identical to what you get on almost any Scubapro high end BCD. One virtue of this system is that you get a rock solid tank mount using only a single cam band. The Scubapro Supercinch bands unhook, so they also pack more flatly than do the conventional cam bands (unless you take the trouble to unthread the buckle on those conventional bands).
The wing is a Dive Rite 27# Travel EXP. I chose this wing because it does NOT have a center panel. Almost any wing with a center panel will be either very difficult or impossible to mount between the backpack and the tank mounting plate. The Travel EXP has only cross straps. I cut out the vertical straps between the grommets and the horizontal strap. All that is needed to secure the wing is the horizontal strap, which fits nicely between the backpack and tank mounting plate and does not interfer with the cam band. I preserved the segments of the vertical straps with the grommets, bungying them down so they don't flop around, only so that I can still install the wing on a conventional backplate later, if I might ever choose to do so.
I use Halcyon harness webbing. Two XS Scuba quick dump weight pockets on the waist strap. And a singel XS Scuba nonditchable weight pocket centered on the single cam band.
That's a 22" corrugated hose on which I actually use an Air2, which was being serviced when I took the picture so I stuck one of my standard Scubapro power inflators on there for the photo. You can get away with a 19" corrugated hose, even with the Air2, but I just happened to have laying around a 22" hose so that is what I use.
The rig has been with me on two trips so far: Oahu and Ambergris. Worked great. In June/July the rig will be with me in the Mediterranean.
Oh, and I only use one SS D-ring on the right shoulder (two are pictured), in case I need to tie off the rig to a boat or something. On the right shoulder I only use a bungie loop through which I pass the corrugated and LP inflator hose. On the waist I use Delrin D-rings and a Delrin waist buckle. There's also a Hogarthian knife--the DSS standard issue one.
More pics of your homemade setup please. Looks interesting!