Qemu

1. Create empty rootfs
1. qemu-img create -f qcow hda.img 10G
2. Download kernel + initrd
1. http://archive.debian.org/debian/dists/etch/main/installer-mips/current/images/qemu/netboot/
3. Run
1. qemu-system-mips -M mips -kernel vmlinux-2.6.18-6-qemu -initrd initrd.gz -hda hda.img -append "root=/dev/ram console=ttyS0" -nographic

Reference

1. http://www.aurel32.net/info/debian_mips_qemu.php