Nope. Do some research. For example, go to
www.head-fi.org and search their headphone forum for discussions about 5.1 headphones. There are also some good articles on
www.headwize.com.
Even if a 5.1 set existed with quality components (for MUCH more $), it is unclear that this would offer an advantage in imaging without some additional processing (crossfeed, filtering, etc.). When listening to an ACTUAL sound source in 3D space (from a home theater speaker for example), your brain is able to locate the source by comparing the delay, amplitude, and frequency characterisics between your two ears. Additionally, the very shape of your outer ear ears effects the sound reaching your eardrum in different ways depending on the source direction (behind, front, etc.). Wearing 5.1 headphones is more like strapping a set of surround speakers to your head. Sound from the rear left speaker of the headphones only goes to the left ear as opposed to both. In contrast, if you listen to a the left rear speaker of a home theater setup, some sound goes to both your left AND right ears. Since 5.1 headphones will effectively get the same signal for each speaker as a proper surround setup, the sound will be as if the source is originating from within your head rather than from the environment without.
5.1 headphones are a gimmick meant to take advantage of those who don't understand how human hearing works.
Think of it this way, you are falling for the 5.1 headphone gimmick in a similar way that someone who knows nothing about graphics cards might go to CompUSA and be fooled into thinking integrated graphics on a PC is good because Intel calls it Xtreme graphics. Maybe this isn't the greatest analogy, but my point is that you need to educate yourself a bit more. Like yourself, I started out thinking that 5.1 headphones was a good idea, but I did some research and ended up with an Audigy 2 ZS coupled with Audio Technicha A500 headphones. I couldn't be happier.