Probably because not much advice to offer!

No matter what the budget its almost impossible to find any decent HP in BD.
The only HP that I can think of is Logitech G35. The only headphone that Offers Discreete 7.1 channel and only HP in the market that is 2nd Dolby Generation certified surround headphone. Razer has Megalodon and SteelSeries has 5H v2, both offers only virtual 7.1 channel.
For 5.1 channel there is only one HP and that is Razer Barracuda HP-1... it is a discreet 5.1 channel HP that connects to any 5.1 Soundcard via 3RCA connector. Basically its a Mini 5.1 speaker system that mounts on your head.
Those are the only headphones I can think of that you might be able to reach from BD with some luck of course. There are lot other surround HP but they are way to rare to get (even in US or UK) and cRRazy expencive. So its not wise to talk about those.
I am using G35 for a long time now and previously used Barracuda HP-1 for couple of months. Tried Megalodon once and never botherd to waste time trying the 5H v2. So here's the verdict,
*G35 - the only Dolby Certified HP with 7.1 descret channel, built with heavy duty Logitech standard (its durable and tougher then G27 ;P) Price around 7500Tk.
*Barracuda HP-1: The only 5.1 descrete channel HP in the market. Jinjira made MicroLab speakers and Indian Maruti cars have better built quality then this piece of junk. Mine didn't even last 3 months... total wastage of money, 6000TK
*Megalodon- Awesome Bass, Bass sounds are killer with the special effect mode on but it messes up the clearity of the surround effect. No descrete surround channels, only virtual. But I must say again.. the Bass sound is nothing like my ears have ever experienced, Best bass ever. Price .. ehheem... 11000Tk. x_X
*SteelSeries 5H v2: Pathetic excuse of a Headphone, they call it loosers gadget. I can't confirm its bad reputation as I never actually botherd to put on it and try, So...! Price 6000TK.
I hope it helps.