Chris,
Take Roberts advice and do it his way or I can make you up a button. I have quite a few of the buttons common in kit games. The self contained jobbies with 2 terminals out the bottom. I'm just soldering on a length of wire, feeding it through a coin slot, zip tying it off for a strain relief, then jumping the coin switch. I am wrapping the body with tape and catching the wire in a couple of turns so its not hanging from the solder joint. Quick easy reversible free play.
That aside...they folks at the EXPO are giving out blocks of wood to go in place of a coin mech. Its supposed to have a switch where the reject lever can hit it. Push coin return and it credits.