The Gen 7 can be ordered with an LS1 option. It comes as a kit that plugs into the existing stock cam/crank/coil connections on the LS1 motors (read this for details). I don't know about finding a used one though, as they have not been on the market that long yet. It couldn't hurt to check ebay.
If you don't find a dedicated system for an LS1, almost any system can be made to work by adding a crank trigger or a signal conditioner/adapter box for the ignition signals. It's just not as simple as it sounds like it should be.
If you don't find a dedicated system for an LS1, almost any system can be made to work by adding a crank trigger or a signal conditioner/adapter box for the ignition signals. It's just not as simple as it sounds like it should be.