OK, now I've got gcc built...I guess I need to get the runtime installed.

[root@big binutils-2.19]# /usr/local/mips64-elf/bin/mips64-elf-gcc -v
Using built-in specs.
Target: mips64-elf
Configured with: ./configure --prefix=/usr/local/mips64-elf --target=mips64-elf --with-mpfr=/usr/local --with-gnu-as --with-gnu-ld --enable-languages=c,c++ --program-prefix=mips64-elf-
Thread model: single
gcc version 4.4.1 (GCC)