If the currency really takes off, then 1000 BTCs could be worth quite a bit in the future. One problem I see with this approach is that the wallet file might be completely unreadable in the future, and thus not spendable. 
That is the exact idea
. Economic growth combined with demand growth in BC's will make a nice return on the investment.The wallet file will have to be "maintaned" obviously, by many backups (printed on paper, engraved?). Also a trust can also be chartered, to legally keep it secret etc.