I've thought about building a game booking and player sign up system that hosts could then take attendence at and feedback so players got show ratings. Like many of my ideas, I never really followed it up (it would cost me money, I've no programming skillz). Brian and I were talking about it again at the FTF game this weekend. Flaking is at an all time high here now. Time to do something.
If players got a show rating, you could they set player caps and your show rating could be used when you sign up. For instance anyone with anything less than a 70% show rate isn't allowed to sign up, and, players would be given slots based on their show rate. So it would be possible for a player with a 90% show rate to displace a player with a lower show rate, even up to 24 hours before a game. That would make people care about their ratings - almost like an eBay rating system.
If someone has the programming skills, I'd be happy to design the concept and oversee its construction - I do software project management for a living.