Of course I did, that's where I found out about PERL_INC. I don't see how modifying @INC or @LIB will help:
$ ~/perl5/bin/perl -e 'print "$_\n" foreach (@INC)'
/home/jason/perl5/lib/perl5/5.8.6/x86_64-linux
/home/jason/perl5/lib/perl5/5.8.6
/home/jason/perl5/lib/perl5/site_perl/5.8.6/x86_64-linux
/home/jason/perl5/lib/perl5/site_perl/5.8.6
/usr/local/lib/perl5/5.8.6/x86_64-linux
/usr/local/lib/perl5/5.8.6
/usr/local/lib/perl5/site_perl/5.8.6/x86_64-linux
/usr/local/lib/perl5/site_perl/5.8.6
/usr/local/lib/perl5/site_perl
.
$ ~/perl5/bin/perl -e 'print "$_\n" foreach (@LIB)'
$ /usr/bin/perl -e 'print "$_\n" foreach (@LIB)'