A bit of Dremel work from both sides created a fine edge that gives me a usable old style lever can opener. 

It doesn't need to be pointed or have a sharp edge , just fine enough to do the job. Once it is puncturing the can OK, you can stop sharpening.

I don't have a big ring of keys, and find myself rooting around in the bottom of my bag for a house key, or not having one. I do always have my bike tool, and I noticed a key sized spacer at one end. 

Make sure that there is enough length clear of the tool to get into any lock you need to use.

To Do:

Replace PH1 with a slim #2. Most bike screw heads, even small ones, are actually #2 not #1. A slim #2 is what a bike tool should have.

Add a 4mm hex drive to use mini tips. The 10mm hex is hollow, and I think a bit of lathe work will let me epoxy or heat fit a 4mm drive sleeve inside it