Iron Crown Enterprises has released the second edition of their popular Eidolon: City in the Sky supplement book for Shadow World. I... wouldn't suggest living there if you're afraid of heights. You know... because it's in the sky and all. "Parachute Maker" is the most respected craftsperson there.
The new version was done by the original author, Terry K. Amthor, so if you liked the first one, you don't have to worry about a big change in tone or writing because of a new writer. The book has stats that fit both Rolemaster Classic and RMSS/FRP, so if you play either of those, this book has you covered. The book is up now on RPGNow, if you'd like to get yourself a copy.