I agree, it sounds cool and I like the idea to get more boys involved, but in addition to the NFL license problems, it would really open a kettle of fish for Ganz. You'd have people wanting baseball, hockey, basketball, and then college football, college basketball--it would be endless.
I can't say about NFL - that will probably open a huge can of worms, license and all - but Ganz should definitely add a local team and its attributes. I see a whole new room theme dedicated to, say, Kinzville Furies. Or should it be "Furries"?
There are some decorations in the WShop that I used on the walls of my sports rooms, my gym, and my diner and bowling alley. A pennant, a red and white banner, a red jersey, and a cheerleader swag. They're generic ("Webkinz" on them), but I imagine them as being sports memorabilia. There's also a football trophy stand. And the POTM blue ribbons from the Wheel of the Month (I have like 7 of those things, and had to come up with ways to use them).