I'm doing something similar with a Sega Megadrive/Genesis.<p>However the plan is, unlike here, to add support for real hardware. For example:<p><pre><code> - reading real cartridges (already have a breakout board for this)
- supporting original controllers (already done, inc 4 way adapters)
- supporting the expansion port (no idea how, but shouldn't be *awful* to do).
</code></pre>
The key to me is the support for original hardware while <i>updating</i> the machine to <i>also</i> support more modern things (like HDD, USB, Bluetooth, Wifi/ethernet, etc)