Bypassing Ignition Interlock
Is it illegal for me to produce and sell?
an artificial device that will] blow [bypass an ignition interlock device (such as those required by drunk drivers)? Also, the market to be used for this purpose?
Perhaps it is not illegal to produce, it would illegal to sell to people for the express purpose of breaking the law. Then you can soon expect to be banned. By allowing them to break the law when they needed an ignition Interlock have, you could be liable (both criminal and civil) for their actions while driving drunk.