why not just configure your different emulators to use the keys you want, instead of trying to change your keys to match the emulator?
there are very few games/emus out there that wont let you customize the controls.
obviously your pinball buttons are flippers for pinball, what do you want them to do in Mame?
i run Visual Pinball in my cabinet, it lets you customize which keys are used for the different functions. Mame will let you customize which keys do what as well. so does zsnes.....see my point. map the buttons to keys, then make your software work with that layout. The only problem i have ran across doing this is DOOM. i found that doom works very well with an arcade control panel, however it will not allow you to completly customize the controls. it will let you change the basic action buttons, but there are no buttons to scroll through weapons, so you have to have a dedicated button for each weapon, and you have to used the number keys..no way to change it. Fortunatly, im using an x-arcade, which lets you have 4 different programmed configurations that are accessable by flipping a switch which i have mounted on the side of my panel. but for everything but DOOM, i dont have to switch it because i customized the software to match my layout.
just a thought...
oh, and i just checked out epic pinball, and man if you are happy with that, then you will love visual pinball, it works well and had a 3d view for a much more realistic appearance. the only issues i have ran into with it is that people who designed some of the tables are idiots and dont use the variables to define inputs. but that is easily fixed. future pinball is also pretty cool and has a 3d interface aswell. epic pinball looks really crappy and is slow, plus you dont see the entire playing field when playing. visual pinball makes it like you are actually infront of the machine, not playing some pc pinball game.