It sounds great, taxing non-residents only. But there is a long history of states trying to do this in various ways, and its always declared unconstitutional. Calling it a "non-resident work permit" isn't going to fool anyone. Indeed its done for hunting and fishing licenses -- but this has been declared acceptable under the constitution. I found a great summary of the topic here: http://www.house.leg.state.mn.us/hrd/pubs/ss/clssnonr.pdf