Can't beat the mitre kit bags. I'm convinced they're custom made to fit the 996 C4. Fit perfectly in the frunk once filled or also perfectly on either rear seat stood upright and come up to the same height as the front seat.
Each bag is a whopping 110 litre capacity!!!! I guarantee no wife is capable of filling one with her holiday junk.
Going back to the OP I saw a nice piece of Porsche branded luggage on display in the OPC opposite the Porsche museum. The price tag appeared to show Euro79 so I jumped on it .......... only to find that the tag related to the silk scarf draped across it.
I didn't get one. I got one for each day of the week in a different colour, although I now have to keep the car outside the garage as it's full of bags...
Joking aside, I did buy a fitted set of luggage which works really well from Roadsterbag for < 1/20th of the price...