$ visitcpan --append=dist -- perl -E 'say shift if -f "Build.PL"'

AASSAD/Catalyst-Helper-Controller-Scaffold-HTML-Template-0.03.tar.gz
ABERGMAN/Alien-0.91.tar.gz
ABERGMAN/File-Find-Random-0.5.tar.gz
ABERGMAN/SVL-0.29.tar.gz
...

##</code><code>##

$ visitcpan -- perl -E 'if (-f "inc/Module/Install.pm") { say "MI" } elsif (-f "Build.PL") { say "MB" } elsif (-f "Makefile.PL") { say "EUMM" }' | perl -E 'while (<>) { chomp; $cnt{$_}++ } say "$_: $cnt{$_}" for keys %cnt'

MI: 2306
MB: 2675
EUMM: 11781