I just don't see that happening.
Even if you could get a sport betting lobby together, the Sports Leagues (NFL, MLB, NBA) would crush it, and no politician in their right mind would write a bill that would allow legalized sports betting in the USA. Poker (A game of skill) perhaps, Sports betting (seen as a threat to the legitimacy and integrity of the multi-billion dollar Sport Leagues)- No.
If you look at all current efforts to legalize on-line poker betting, you better believe there are "opt-out" clauses for the Sports Leagues and States because the Sports Leagues will destroy those efforts. (See the Frank proposal.)
On-line sports bettors in the US have only one knight on our side, the WTO, becasue the WTO is getting tired of the US govt. throwing its weight around in international finance and various legal issues.
There is a European gambling association (?) that works on these issues outside the States, and if the IGC saw any openings in the USA for legalized on-line sport-betting (on Vegas' request?) I am sure they would step right up with all the potential cash waiting to be made.
http://www.igcouncil.org
A previous thread was also posted on the issue:
How many of you would join a Sports Players Association?
Let's hope that the unenforceable UIEGA will keep things the way they are for awhile, and the banks still believe the US Govt. will only look to prosecute the owners and employees of the off-shore books.