Memorize your private key and delete any trace of it, having used a secured offline pc.
So let's say someone knows that I own a large sum of bitcoins. What's to deter someone from holding a gun to my head and threatening to kill me unless I tell them my private key?
Point being, holding all bitcoins in 1 wallet doesn't seem too feasible.
You should try some deniable encryption technique, and hide your Bitcoin purchases with the noise of the network.