TBH i think you would have betetr chances if you had PC's as well as consoles.
In Denmark almost every net-cafe has gaming computers, and are used for gaming (never seen any1 enter one just to check their mail and surf the web) But i've never seen a console-cafë, so either you're original, or people has just thought of it, tried it and failed.
So get a few rows of gaming pc's and some couch sections with consoles.
Remember that consoles take up MUCH more space per player than pc's so you'd have to get a big place (Assuming every consoel gets at least a 3 man couch and a decent tv (full HD for ps3/xb360)
Also, when people go to net-cafés to play PC, it's usually cause they wanna play togeather, and don't really feel like/is able to drag all their PC's to one of them and have a LAN party.
But most gamers already have a console, or know someone who has, so they can just go to his place to play, unless they wanna play multiplayer online with each other.
Point is, only a few PC games has hot-seat multiplayer, but many console games already has split screen or something like that, so theres less "need" to go somewhere and pay for it if you wanna play togeather.
You could also hire some hot chick to work top-less at the place durring the late hours. That should draw costumers.
I wish you the best of luck if you decide to go through with it.