I think your idea is an excellent one, but I would make one suggestion to you:
Look at changing the format of the game!
Buying the NPPL name would be an excellent start, but you need to be able to win over more players into playing the league in order to keep it running.
Lower cost venues will help lower entry fees, but you still need to come up with a format that will draw players to the league.
Perhaps this would be an excellent time to solicit from the masses suggestions on a completely new format that somehow combines the best of both leagues. I'm sure that the collective community could develop a completely new format to meet the needs of both 7man and Xball camps.
The format would need to be easier on the wallet (ie paint consumption) and provide a fast paced game that's appealing to players and audience alike.
Once a format is decided on, a regional format that feeds into a national series title would an excellent way to draw teams into the series. Many teams can afford regional travel, and having 4 or 5 qualifiers in a region would allow teams to play the format in these trying times.
Top teams in each region would be eligible to compete in a World Cup style finale. The "Cup" would have a separate tournament running at the same time to end the year with a bang.
Perhaps a good prize for the regional winners could be all expenses paid to the Cup (in addition to any other event prizes)? A portion of the regional revenue could be set aside for cash prizes to the National Finals
I know it's kind of rough, but I'm winging it here