For the 7-Seater, 2 piece trunk mat in Gray (Interior code CUSU, CU0P, CBSB, CBQX, CX0X, CX7X) is PN 39988920, 2 piece trunk mat in Oak (interior code CX8X, CF3L, CF90) is PN 39988923. Beige (interior code CX1X) is PN 39883588. Interior code is located on the small plaque in the right rear passenger "B" pillar.
From what I can gather (looking at part numbers), there are 3 types that "should" fit a 7-seater. A single plastic mat with a bending split in the middle, a 2-piece plastic mat (dunno the PN, just saw photos), and a 2-piece cloth/rubber reversible mat. I have the single plastic mat in my '05 (mines a 5 seater but see the split for 7) and the cloth/rubber for my '08. I gave you part numbers for the high-buck mats from VIDA and they're correct but I have no idea as to what makes them so expensive. In looking back, I would not spend that kind of money ($200+) on a cargo mat.
If you're looking for a decent split mat, I think PN 30681892 in Gray (looks like that's what you wanted for color) is the better deal and you can have it either textile on top or flip it over and have rubber on top. That's the one I have in my '08, great fit and I have no complaints. You'll lose the water holding capability of the split plastic mat but if that's the direction you want to go, Weathertech sells a good one for a reasonable price in rubber.
Apologies for the confusion with the high buck PNs.
I have the two piece plastic mat and don't have any complaints. I think it's a slick design. Won't hold gallons of water but has held up to the few spills and various dirty/sandy things we've had in the back. I was unaware of the "bending" mat but that sounds pretty cool as it can be annoying sometimes with the split mat when putting the third row up.