I have attached two pics of my homemade travel rig. I only have a house scale, so not accurate to the oz, but it weighs under (probably just under) 5lbs. I prefer the hard backplate to a soft one. This rig has 3 trim weight pockets (holds up to 15lbs). Here's a fuller description:
Scubapro Plastic BP (poached from my old Knighthawk; it's slightly curved at the waist and has a narrower tank mounting plate than the older SP backplates).
Dive Rite Travel Exp Wing 27# - To install the tank mounting plate, I had to clip the sections of the center vertical cross strap between the grommets and the center horizontal cross strap (the grommets are still there but not being used; I simply tied them down with zip ties; the wing can still be used and locked down on a conventional backplate, but I have other wings for that

.
16" corrugated hose, Scubapro inflator.
Halcyon harness (lighter and softer than most); two bent SS D-rings, two Delrin D-rings; Delrin waist buckle.
Two XS Scuba Quick Release Weight Pockets on the waist band (5 lb capacity each)
One Scubapro Tank Cam Band with an XS Scuba Quick Attach Trim Weight Pocket (5 lb capacity)
Tank locator strap (3/4" nylon webbing; one locking tri-glide)
One tiny knife on the waist belt (DSS standard issue)
I think that's it. Extremely light, just under 5lbs, with only one cam band, weight pockets, a knife, and solid backplate stability. Plus the built-in SP carry handle to boot--it's ready for the road!