I will make that easy - I will buy any and all bonds for 0.005BTC each.
Just say how many you want to sell, and post it in a message signed with you BitFunder associated address to prove ownership, and then if and when BitFunder shuts down I will pay the BTC and take control of the shares. You will need to email the message to both me and Lab_Rat to confirm the change of ownership though.
The above is somewhat tongue in cheek with the price offered as I don't want to be held to something which I later regret, but the method stands in principle, and I will still happily buy any at that price!
But yes, your point is valid in that it will be hard, just not impossible.