I think you'd be surprised at the number of women and girls that would pay money to show up and support a women's team in Minnesota. Girls hockey is very popular, obviously not to the level of boys, but this state has done a very good job building the game for girls as well.
I wouldn't expect something like this to take off immediately. It would have to be nurtured and supported a bit by the NHL...but after a while, it may grow to the point where they could be largely self-supported. Plus, think the of the PR the NHL clubs could garner by doing something like this. Right now, with most of the marketing done to appeal to a largely male fanbase, they could be tapping into a mostly ignored base of fans that make up half the population.
Start off small....maybe 4-6 teams placed strategically in markets that have the best chance of being supported: Minnesota, Winnipeg, Toronto, Montreal, Boston and New York for starters. Then try and branch out from there. Maybe a 30 game schedule to start, which would grow as the number of teams increases. Salaries would be modest, under $50,000 per player or something like that.