As soon as I read the words "converter chain", it set off a little itch in my brain somewhere. Sure enough, Seam has a converter chain.

http://anonsvn.jboss.org/repos/seam/branches/community/Seam_2_2/ui/src/main/java/org/jboss/seam/ui/converter/ConverterChain.java

I'm pretty sure somewhere I have even written about it, but that memory has sort of faded.

I can't believe we didn't push for this in JSF 2.0, but let's just say that we were already advocating on too many fronts and we simply didn't have enough guns ;)

-Dan