I love this argument about why the Vikings get a stadium.
First off, the Vikings play 1/2 of their games outside of the state of MN. Players are taxed where the paycheck is earned, meaning the players are taxed where they play. So $50 million would be available to be taxed by state income tax. The state income tax rate is 7.85%, which equates to $3,925,000 in tax revenue.
http://articles.latimes.com/2009/apr/12/sports/sp-jock-tax12 &
http://taxes.state.mn.us/publications/pages/press_releases_content_2010_income_brackets.aspx
The Vikings Operating Income (not final income, final income likely lower) was $18,000,000 in 2009. The state corporate tax rate is 9.8% which means the tax revenue would be $1,764,000.
http://www.taxfoundation.org/taxdata/show/230.html
http://www.forbes.com/lists/2010/30/football-valuations-10_Minnesota-Vikings_309201.html
Factor payroll, sales tax, income tax on related businesses, and property taxes (Winter Park), and I'll give you $25,000,000 for that (vast over-statement).
Total tax revenue would be roughly $30,000,000.
The Vikings have said they'll pay 1/3 of a stadium that costs at least $700,000,000. That leaves the MN tax payer to borrow $466,666,666. Minnesota will have to finance that up front since we have no surplus. If MN used the $30,000,000 in tax revenue from Vikings to pay off the stadium bonds, it would take 40 years (assuming bonds not callable or callable at a premium) to pay off (assuming 4% interest, slightly higher than 30 yr treasury yield). Even if it quadrupled the Vikings income, it would take 27 years. Either way it will be well after the next time the Vikings hold their fanbase hostage while threatening to leave asking again for a new stadium.