yeah it's tough to find a good multiplatform that doesn't break the bank. that being said, the Tactic 3D Omega
is actually pretty decent. It is wireless though, but supports dolby and thx surround sound. http://www.headset-ratings.com/sound-blaster-tactic-3d-omega-headset/
They were $200 when they first came out, but they've since dropped in price, I believe around $140 now. I've owned a pair for around 18 months and they've worked well so far. the range and mic clarity is excellent, and the soundstage is pretty wide. precision in positional audio was surprisingly good too - noticeable change when playing CS, BF4, COD, Crysis, etc.
its unfortunate there aren't more multiplatform options, but this is one of the better ones, and it doesn't cost $250+ like the A50
hope this helps! happy gaming