Here’s a pair of smartphone dock designs that pay homage to a time when we plugged cartridges into other cartridges to play games. Back in the early 90’s such adapter cartridges like Sonic & Knuckles, Super Game Boy, and Game Genies were pretty cool, you kids will have to take my word for it.
The docks make for a neat way to charge your phone, or to play games if you have one of those nifty 8Bitdo game controllers. There is a power indicator light on the front to let you know the phone is charging. The phone charging cable plugs into the back. A pair of USB ports and a headphone jack is also located on the back.
You could also sit your phone on both docks vertically, if you need an easel for widescreen gaming.
The above Genesis/SNES cartridges in the docks are the same size as the originals, the one exception being the slot for the Game Boy paks on the Super Game Boy is 4mm wider for the iPhone 5 to fit (would need to be 12mm wider for iPhone 6). The Sega Genesis base was also shrunken down by about a third.
I can see Sega licensing this product for manufacture, as they’ve been known to do with their legacy consoles. Now that Nintendo is making mobile games, they might also be open to making such phone accessories down the road.
Dave's Geeky Ideas 
I would love one of these from my iPhone 6 Plus I like the nostalgia of it Or better yet make one that will fit an iPad or iPad mini 4
I think the iCade is best for tablets.
I think really what I meant to say though is they need to make one to fit the iPhone 7 Plus and possibly the iPad or iPad mini’S to give people the options
Tablets are too big. I wanted to make docks that are nearly 1:1 in size with the original consoles and cartridges. Maybe one day I will drum up something specifically for tablets.