Video: Long before the Nintendo Classic came along, Sega let all kinds of companies make micro-sized plug and play systems. The Radica was one such system, and as these things go, someone was bound to put a Raspberry Pi inside one. Enter YouTuber Michael Lyons.
This uses a Radica Genesis purchased cheap off eBay, which happens to be a near-perfect size for a Raspberry Pi 3. All Lyons does is take the mini-Genesis apart, cuts out a few parts of the case with a dremel, then crams the Pi inside. If you long for the days of Sonic and Altered Beast over of Mario and Zelda, this is the Pi case mod you've been waiting for. Head over to YouTube for the full guide.
Radica Genesis [YouTube]