I have no idea about curses, but would it maybe be possible to stop the timeout (or set it real high) and do something like:

while(1) {
    my $chr = getch();
    if($chr ne "\n") {
      push(@someary, $chr);
    } else {
      print "\n"
      last;
    }
}
[download]

I'm not sure if this would help you at all, and I haven't tested that code, so take it with a grain of salt.