Europly might be fine, Chinese ply from HD, no way.

I've made structural beams from ply before.  They are quite strong- a good glue bond is essential.  Alternately, you could back up the glue bond with some bolts or stainless screws.  It would look good with the exposed ply.  Just use carriage bolts and recess them with a forstner bit, very strong and certainly strong enough for a bed.  There is a guy who I saw at the Dwell show in LA that makes entire houses using plywood, so strength is not the issue.  That said, the crap from HD is not a good idea from an indoor air quality standpoint.  If your HD stocks it, the Columbia Purebond is a perfect material for this-at 50.00 a sheet it would likely even be cheaper than lumber.

Check the Canadian Plywood association site out.  http://www.canply.org/english/literature_media/plyplans.htm  The even have a free downloadable plan for a bunkbed that looks pretty good.  I would even substitute a double layer of ply for the 2x4 that they use for rails. 

Gregg Fleischman's stuff is super cool. If the dimensionality of the plywood is consistent then making a couple of router jigs could generate endless designs. A new library in Seattle has similar kinds of furniture in the kids area. Honestly, not super comfortable but for loved the exposed simple slotted joints. Thanks for the link! Good point about using cheap ply from China for kids furniture. We've got a good distributor of hardwood ply here and I'll see if they stock either Europly or the Purebond stuff.

Have always been a big fan of kerfdesign's work and first saw their stuff at a shop in Ballard when we used to live in Seattle. Noticed they've gone to using CNC which is perfect for the precision they need to create their work. Good stuff indeed!