All X68K emulators support MIDI output to real modules. You just need an interface that is compatible with your version of Windows, and a lot of the cheapo generic cables will not work on anything past XP, some will work on V/7, but not all.
When MIDI is enabled in the emulators, they simply send MIDI data to the windows default midi device, which will be the awful WindowsGS SoftSynth. So you need something like Putzlowitschs Vista-MIDI Mapper Control Panel addon to actually tell Windows to use your real MIDI interface as the default MIDI device.
Regarding X68K MIDI support, it depends on the game. Most games are meant for Roland LA (MT-32) or Roland GS (SC-55). The Akai does not support either of these formats, it's pure GM, so it will not function correctly with most games. SuperSFII is one of the few games on the system to use pure GM with no extra enhancements.