For that matter, there's "Atomik Aliens" on Drive Thru RPG and elsewhere, which starts with prokaryote/eukaryote/silicate/artificial and works up from there.
However, I was looking for finished examples. For that matter, I'm looking less for detailed biological underpinnings and more for unusual concepts and mind-sets. Maybe I'm setting the standard too high ... nobody's met an alien (anal-probe wielding Grays not withstanding), so we fall back on familiar patterns: humans, animals, plants, mythological creatures, etc.
"On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question."
- Charles Babbage (1791 - 1871)