I'm hoping someone here who has more experience using Kuroneko than I do can answer this one -- I want to send a package from Kyoto to NRT roughly a week before departure and pick it up before my flight. (Basically, I'm going to be buying some stuff in Kyoto and then traveling for another week before leaving, and I'd rather not haul all this stuff around with me if I don't have to.) Yamato's Web site seems to suggest this isn't doable, but they also seem to contradict themselves:

I'm a Japanese illiterate so I can't really tell whether these two statements are, in fact, mutually opposing or whether something's been lost in translation. If I read the statement correctly, it seems I can select a delivery date that is a week in the future from when I turn things over to Yamato -- is this right? Or is there an easier way to do this that I'm overlooking?

Thanks in advance.

>I can select a delivery date that is a week in the future from when I turn things over to Yamato

I think so.
If you happened to buy things few more days than a week before your
departure from NRT, you may ask at your hotel if they can ship things
out with Yamato on behalf of you
(you fill the shipping labels and fee and leave them at the hotel, off course).

Terrible Kuroneko translation. As a Japanese native speaker, I understand this as:

At an airport, Kuroneko's storage service is only offered when you have used their transportation service (空港宅急便、くうこうたっきゅうびん、kuukou-takkyuubin) to the airport.
Maximum days for the storage is seven.

Your understand is correct.
You can send your luggage 7 days in advance before your departure date.
If you need to send your luggage more than 7 days in advance, you can follow LosPenguinosII's advice.