This may not apply to your ideas since it's more of a PC-centric business [lounge with ridiculous numbers of decked-out gaming rigs loaded with almost any major game you can think of, with the ability to bring your own] with a side-focus on computer training and consoles [big screen, LAN setup, rent-to-use, last I checked]. However, some of it may be of use...
http://www.pghcyberconxion.com/
I haven't been in the area in years but they opened during my last year in Pittsburgh and they're still going strong. Some of the keys to their success, I would guess, would be...
(1) They had a full set of established rules regarding minors, ranging from behavior, curfew, and game content. It was very thorough and quite accessible, even though I can't view it on the website. Essentially, if I recall, there was a point at which the young'ins were kicked out for the evening (usually applied more on weekends when they were open until 2 AM), and worries about game ratings were covered by a comprehensive parental permission form, if you will.
(2) They made PLENTY of deals with nearby businesses to various ends. Since they ran parties on the side they had deals going with the local Cold Stone across the street (coupons, cheaper ice cream cakes, etc.), a pizza place down the road, a nearby Chinese restaurant, and...shockingly, the EB further up the block (minor deals on used items, show a "used" purchase to CC and get an hour of free play, etc.). It certainly worked in their favor, especially when you would get a group of friends in there, a few hours pass, and then you can order a pizza for a good discount? Sweet.
It also helped greatly that all of the workers there were older (35+) and were completely knowledgeable about PCs, Macs, consoles, whathaveyou. The place was run well, well-stocked on drinks and whatnot, and was a generally good place to be. That's all back in 2005, though, so I don't know what other changes they have made since then. Try asking any resident Carnegie Mellon / U Pitt / etc. students around CAG to see if they have any more info.
Yeah, no actual games sold or bar, but maybe some aspect can serve as inspiration.