Well, in an attempt to answer my own question, I tried to compile the ext2 image, the idea being that I could mount it on a loopback and look at it. Alas, I am getting this with a file system size of 6 MB:
/home/local/kamikaze/trunk/staging_dir_mipsel/bin/trx -o /home/local/kamikaze/trunk/bin/openwrt-brcm-2.4-ext2.trx -f /home/local/kamikaze/trunk/build_mipsel/linux-2.4-brcm/loader.gz -f /home/local/kamikaze/trunk/build_mipsel/linux-2.4-brcm/vmlinux.lzma -f /home/local/kamikaze/trunk/build_mipsel/linux-2.4-brcm/root.ext2
mjn3's trx replacement - v0.81.1
fread failure or file "/home/local/kamikaze/trunk/build_mipsel/linux-2.4-brcm/root.ext2" too large
make[3]: *** [install] Error 1
make[3]: Leaving directory `/home/local/kamikaze/trunk/target/linux/brcm-2.6/image'
make[2]: *** [image_install] Error 2
make[2]: Leaving directory `/home/local/kamikaze/trunk/target'
make[1]: *** [target/install] Error 2
make[1]: Leaving directory `/home/local/kamikaze/trunk'
make: *** [world] Error 2
If I reduce the file system size to 4MB the build fails because it doesn't have enough space....
--Yan