The problem with hacking a keyboard like Peale describes it is that you are using non standard keys and must therefore remap everything in Mame. Also, you no longer have stanard mappings for menu programs, e.g. a menu program such as ArcadeOS that assumes cursor key movements for the joystick and p1/p2 start buttons on #1 and #2.
Yes, Peale's method IS the easiest keyboard hack, but be aware of the mapping changes.
For only 8 inputs, I too would go with keyboard hack, or if using windows, I'd hack a Gravis USB gamepad (10 inputs) But be aware you will need another method of selecting games if your front end doesnt allow you to remap keys to do different functions.