r0ni over at
http://sdlmame.lngn.net/ has been providing OS X SDLMAME builds for a
long time. My builds are just an alternate source with a couple minor differences.
* support OS X 10.7+
* both 32bit and 64bit are built at the same time (always current)
* SDL framework installation
is not needed or used, just unzip and run.
https://build.btolab.com/project/sdlmame/