I have a Quicktime on my ERA and it is a very nice piece. No machining required. Also, there is now a starter pocket cover available at a very reasonable cost. I have one, but have not yet installed it.
What about a Ductile Iron Bellhousing? I was thinking about casting one using an aluminum as a pattern. As stated above Cast Iron may break or shatter but Ductile is much more resistant to cracking/breaking.