I am surprised by the numbers given for the annual cost of a safe deposit box. We used to have one and it came free with our checking account, which was at a certain level of whateverness (ruby, silver, tungsten?).
Something you might want to check into if you’re thinking along these lines.
Banana Stand. Duh.
I am sorry to say that if 7k+ means under 8.000$ in total and you want to buy a home, your problem is not where to hide 5 lousy ounces of gold, it is where to find a lot more money.
That is, if a kilo is a thousand. Now, if 7k+ means seven million dollar (in Spain un kilo means one million, as thousand one-thousand-pesetas bills weighed one kilogramm when we had pesetas as a currency), then your problem will become weighty.