I don't have any numbers regarding 2L summer employment. I'd say that most people do have paying jobs - but not those fancy "Summer Associate" jobs. A lot of people are relying on smaller firms, government, public interest, and anywhere they have a connection (uncle's firm or whatever).
That's not to say that people aren't getting big firm jobs - a lot of people are. Probably 30% or more (this is just based on asking around - no numbers). I'm under the impression that the number was a lot higher when times were good though.
Still - there are those (myself included) that just had really bad luck this year. I have two part-time jobs, only one of which is paid. How do I afford my rent? I don't. I'm borrowing from my dad this summer. It's only a couple grand - not a big deal when you consider that you're spending about a grand a week just to go to class during the school year. (Plus my dad gives me 0% percent interest.)
With a little luck - and perhaps a new president, there should be many more options by the time this year's class reaches the second year.