If speed doesn't play that important role, but readability does, I would prefer to use a module:

use Sort::Naturally;           # from CPAN
foreach $orf (nsort keys %mips) {
    push @mips, $mips{$orf};
}
[download]

or perhaps also written as

my @mips = @mips{nsort keys %mips};
[download]

Greetings,
Janek