Although FreeBSD/mips has been committed to the tree, a few stragglers haven't been pushed into the tree for various reasons. Oleksandr Tymoshenko and I have been honing them down and have just published a set for review.
If you'd like to try FreeBSD/mips out, you can grab these patches from Oleksandr's directory. There's four diffs included. Please send any feedback to email@example.com.