This looks like they took one of those cheap Colby headphones and stuck a bunch of transducers in it and called it surround. There actually are some 5.1 decoding headphone units that are apparently fairly good.
Pioneer Dolby Digital Headphone Unit - and you can even use your own headphones with it, thankfully (the supplied ones look like something out of a cheesy sci-fi movie).
Sony 6.1 Digital Surround Headphone System - Sony has actually had a surround headphone unit out for quite a while now, this is the latest iteration.
Supposedly they both do a pretty darn good job of creating a 3-dimensional soundstage and work well with movies. Sennheiser had a little surround dsp processing unit at one point too. The Pioneer and Sony units are way too expensive for my tastes, but I guess if you NEED your movies at high volume and in surround sound but can't use speakers, you've got some solutions.
