I have posted new Intel builds of Firefox, Thunderbird, and Camino. You can get them here. As the page says, I build these myself whenever I have the time, and they may contain patches that are not in CVS yet. These builds are the best builds I know of for the latest Apple seed builds, not necessarily the newest. Use at your own risk.
The current builds require the latest Intel Mac OS X seed, 8F1099. They seem to be very stable.