At this link theres some talk about how to make a spark plug socket wrench with the help of a dremel tool to make a pin lock tool. I think this is cheaper than converting your pin kegs to ball kegs, $5 for the spark plug wrench, either 13/16 or 7/8 depending on what you got on your keg, a dremel tool(come on, who here doesn't already have one!) with common cutting disk and a workbench vise to hold still while cutting the socket. I have to say that the workbench vise comes in handy for a multitude of projects.
Just mark the socket were it contacts the pin lock posts with permanent marker and cut away until the socket seats deep on the posts. Fun project!
This post goes into greater depth on the variation of socket sizes that are out there...
"Labor is prior to, and independent of, capital. Capital is only the fruit of labor, and could never have existed if labor had not first existed. Labor is the superior of capital, and deserves much the higher consideration." Lincoln's First Annual Message to Congress, December 3, 1861.