Corion's approach is better than this (building and applying a single list of indexes is less work than repeated array mutations), but the reverse/splice dance you had in mind might look something like this:

use Modern::Perl;

use Test::More;

main();

sub main
{
    my @foo = (1 .. 8);
    my @bar = reverseswap( @foo );

    is $bar[0], 2, 'swapped the first one';
    is $bar[1], 1, '... with the second';
    is $bar[2], 4, '... and so on';
    is $bar[3], 3, '... and so on';
    is $bar[4], 6, '... and so on';
    is $bar[5], 5, '... and so on';
    is $bar[6], 8, '... and so on';
    is $bar[7], 7, '... and so on';

    done_testing;
}

sub reverseswap
{
    my @array;
    push @array, reverse splice @_, 0, 2 while @_;

    return @array;
}
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