Raised platform bed for my son. Will it hold?

Hi all,

I'm in the process of planning a makeover of my son's room. I currently have this made in Sketchup: http://we.tl/KLORisIxJN

The Sketchup file is layered so you can easily turn on/off to see what's underneath. For those of you without Sketchup, here are some images:

http://imgur.com/a/vC6Po

The idea is to have 3 Ikea Malm cabinets and a 'frame' from 7cm (2" 3/4) square beams to support the structure. The matras will be supported by a 3/4" plywood that's meant to be used in concrete forming applications. It has non-slip properties. Although the sketchup and images don't reflect this, I will be making several, evenly spaced holes in it to allow the matras to breathe.

The crawl space would be used for storing some of his bigger toys that don't fit inside the Malm cabinets.

My main concern is if it will hold up in the long run. My son will likely push himself up on the platform each time. On top of the cabinets there will be hardwood panels that should help a great deal in dividing the weight, but I'm not sure it will be enough.

Ideas:

• In all likelihood he'd be getting on the bed at the point closest to the door, so I could move the cabinet at the footrest towards the wall and put a support beam in between the 2 cabinets, to make the weight on top of the panelling supported by those. This would be less pretty though.

• Put an extra beam on top of the cabinets supported by 2 extra legs in the corners (side of the desk)

Any input is welcome, especially constructive criticism. I am new to woodworking / DIY, so be gentle :-)

Cheers, K!