Is there a currently available way to connect firewire to a 2011 MacBook Air besides the Apple Thunderbolt monitor?
Nothing shipping immediately, however Sonnet did announce a Thunderbolt ExpressCard adapter  that you could pair with a Firewire ExpressCard to give yourself some Firewire capabilities. Their site claims it will start to ship by December 14, 2011. At one point a   direct Thunderbolt to Firewire adapter was announced, but I can't find any concrete info on it, so I wouldn't count on it appearing any time soon.

Overall Thunderbolt support from anyone other than Apple has been pretty slow to take off. There have been some suggestions that Intel was slow releasing final specs for manufacturers and/or getting production hardware out the door. I've also read that some manufacturers may be waiting for the 2nd generation of cheaper Thunderbolt chips to ship sometime in 2012. Lots of promise in the technology, and I think it will take off sooner or later, but it's still in the early stages unfortunately.