Abrial, I have been through your thought process. Here is my solution.
http://www.masterlock.com/product_details/...Padlocks/1500iD
Do take note that you may have to check your padlock eyelet size as this lock is not very big. I had to grind down and cut away some metal from my HDB gate eyelet to fit this lock. But glad I did. I got some grinding stones to fit on a drill and slowly grind away the metal. Make sure you wear googles and heavy gloves for protection.
You can buy this revolutionary lock at Home-Fix. It uses movement rather than numbers to open. You can open the lock blindfolded.
I don't carry any keys to my house anymore. My maindoor uses a digital lock.
Have fun.