Here's my contribution; it still works in 0.9.1!
Please forgive any horrible hackiness you find -- this code was never written for public consumption :)
who(11): (tree-to-string '(:body (:b "Foo bar") (:i :style "baz" "boo"))) "<body><b>Foo bar</b><i style='baz'>boo</i></body>"
-R