Encode::First is now going to CPAN, or can be downloaded from my svn repo: http://svn.bulknews.net/repos/public/Encode-First/trunk/
Thanks to Juerd and Aristotle for valuable feedbacks.
Meanwhile I found another bug in Encode::JP::JIS7, which encodes all un-encodable characters into PERLQQ format, when we specify "iso-2022-jp" as an encoding. This is a serious bug and reported to Dan and on perl-unicode mailing list: http://www.nntp.perl.org/group/perl.unicode/2007/03/msg3054.html
Actually this bug was reported 6 months ago because of the other problems, where other FB_* fallback flags are completely ignored. Hope this patch goes in.