Our resident hockey team wants to connect a laptop to one of our HD-250 cameras via firewire while we're broadcasting. The camera would be connected to a TriCaster via the BNC output terminal.

Is this possible?

Whether it's possible or not, it's DANGEROUS to the FW port on the camera, which I ASSUME would be moving to follow the action. The FW ports on the JVC's are NOT all that robust and that sounds like a prime opportunity to blow the Firewire chip.

I would recommend them getting a seperate video (analog or digital) video to firewire converter. That way all you need to do is deliver your signal.
You could deliver CVBS with dual analog audio, component with dual analog audio or split up your HD-SDI signal with a seperate splitter. That is, if they even need the audio from the camera.

Composite would be the cheapest to get a converter for, but would obviously be SD.

Yikes. Thanks for the heads up!

Maybe I'll just tell them to bring their own camera/laptop setup. They're using the footage to keep track of stats using X's and O's software or something.

interesting thought though, for example run a firestore and a nano flash at the same time instead of using hdv tape as your backup