Good blog write up about Apocalypse Punk and some of the variants of the setting that could be great fun at the table. I have recently been thinking back to some of the games I have run over the years and wonder if Rifts could be tweaked and make a great setting for a game like this.
New setting wise there are plenty of options for running games in this style. The Cypher system is just begging to be run like this. FATE would be an easy choice as well. Savage worlds Interface Zero 2.0 would put tons of tools in your hands for a game like this.
Just a few thoughts.