Michael, the hybrid cuben is not far lighter than any of the xpac and xply fabrics Dimension Polyant offers:
Hybrid cuben described by OP: 2.9 oz
WX07: 3.6 oz (0.5 mil film, dacron diagonal reinforcement, 70 denier nylon face fabric)
VX04: 3.0 oz (as VX07 but with a 40 denier nylon face fabric)
TX07: 2.8 oz (advertised as 2.6 oz, two layers 0.25 mil film w/ 800 denier dacron fibers between and 70 denier ripstop nylon face fabric)
TX02: 2.4 oz (as TX07 but with a 20 denier nylon face fabric)
PM02: 2.2 oz (Nemo's earliest airbeam fabric, 500 denier dacron scrim + 0.5 mil film)
These are all laminates composed of a woven nylon or polyester face fabric (except PM02), a grid of diagonal reinforcing fibers (Dacron), and PET film. They are exactly the same thing as the hybrid cuben, but with Dacron reinforcement instead of Dyneema. I'll grant that some of these materials aren't easy to find from vendors, and must be obtained directly from DP (and they don't always have affordable roll-ends or short lengths in stock), but the hybrid cuben has no weight advantage over them. Incidentally, none of these DP fabrics cost more than $15/yard.