Hi all, i'm going to show you the way i've got a few laptops.
This method does require a little effort, and one key component; DRY ICE.
Dry ice is frozen air, and evaporates into nothin which is what we are exploiting.
http://en.wikipedia.org/wiki/Dry_ice

Also, i was in a rush when i made this, there a few ways to make this alot more neat/tidy but unfortunately i did not have the time.

Now, to get dry ice you must find a supplier. This is the hardest part.
A simple google search will be your best bet.

Dry ice is the best thing to use for boxing end of story, the beauty of using dry ice is this;
Leaves no residue
Leaves no trace of anything whatsover
Can spoof weight amazingly

Down here at Mittaa laboratories we ran a few tests, here are some retention tests of dry ice wrapped once in cling wrap.

Batch one: 65g at 7:13
29g at 8:16
Thats an hour and 3 minutes time at room temperature.

Now with a bigger amount, and longer time frame.

208g at 9:32
122g at 11:17
Again, a massive loss in weight in the space of around 2 hours.

So roughly, depending on how much is in each parcel (Keep in mind, bigger lots of dry ice do take longer to evaporate entirely due to the amount of cold coming from its surrounding ice) dry ice loses around 25%-50% of it's weight hourly.
Again, i cannot stress enough, the bigger the amount the longer it will take to evaporate.
The best time to post Dry ice is a Friday afternoon, around half an hour before the post office shuts. This will enable a whole weekend (or night) of evaporating, and by the time it gets to it's destination it will have evaporated and there will be nothing in the box except for your insulators used.

Now some pictures of the actual process.

What your going to need
http://i.imgur.com/osg1S.jpg



Lay dry ice on cling wrap.
http://i.imgur.com/nZISq.jpg


Put desired amount in the centre of the cling wrap, and wrap till it is a neat little parcel.
http://i.imgur.com/WPNlh.jpg

Here are examples of two parcels (3.5kg in weight, for my item i was boxing).
http://i.imgur.com/Q2KZz.jpg


This step is so important, i cannot stress it enough. Make sure to cut slits in each parcel, this lets the gas escape from the parcels and weight to drop. As the dry ice is evaporating it NEEDS to escape. Cut around 4-6 slits, evenly distributed.
http://i.imgur.com/2sGoT.jpg



And now, the final step.
Wrap the parcels in some insulation, this helps to keep the cold away from the surface and also add legitimacy to the parcel itself when said company opens it. I use bubble wrap, but you can use newspaper etc. Leave enough openings for the gas to escape out of glad wrapped parcels.
http://i.imgur.com/ylguO.jpg


Now, this is what the finished product looks like.
http://i.imgur.com/jzCpD.jpg




And there you have it!
CRUCIAL STEPS;
Make sure you cut slits in glad wrapped packages.
Put some newspaper at the bottom of the actual package itself (Prevents cold from penetrating bottom).