This is a tough one, on the one hand women's hockey needs some sort of pro league. On the other hand I really question how successful one could be.
I think the the most difficult obstacle would be money. Assuming this league would be placed in the northeast, some of the players would be coming from different parts of world and would need some sort of monetary compensation. You would also need owners, paying fans and lots of sponsors as has been mentioned already.
I think something that could be viable, at least for the time being, would be a very small league (think 4 teams) maybe in Ontario, maybe a little more spread out that plays weekend tournaments. All 4 teams congregate in one teams city and play the other 3 teams, 2 games a night: Friday, Saturday, Sunday. Charge admission once for the entire weekend and have these rotate through the 4 towns. If this league could partner up with the CHL, they could have a Memorial Cup esque tournament the same weekend in the same place. Include tickets to the women's games with the Memorial Cup packages and create a reputation. I think there's a good chance you could convince jr hockey fans to come watch some of the best female hockey players in a championship environment and I think this kind of league would work.
Now of course the main issue here is that a league like this would not be a big money maker, therefore the players would not be paid well. I imagine that the majority of Canadian/American women are based out of eastern Canada or the Northeast somewhere and could afford the time to play if a team was near enough. The National Lacrosse League operates off of a similar weekend schedule where the majority of players have day jobs and make very little from playing lacrosse.
The goal here would be to get something going and hope that eventually interest would build and a legitimate pro league could exist for women's hockey. In the meantime at least some form of a league would exist and I could definitely see TSN picking up a few games, much like the NLL.