You'd think that following the unspectacular performance of the Game Gear, Sega would have learned that huge, expensive, battery hungry handhelds based on pre-existing consoles don't that well. Apparently Sega didn't. They went on and released an even huger -though admittedly beautiful- console, that was big enough to play proper Genesis cartridges and powerfull enough to drain its batteries in a couple or so hours: the SEGA Nomad. It was of course a flop, but also a lovely little thing for us retro gamers and collectors.
You can bid on said handheld via this Genesis Nomad eBay auction. Seller ships worldwide and is including a Nomad carrying case and three games (Flashback, RoboCop vs. Terminator and Sonic & Knuckles). Expect to pay quite a bit more than 100$.