Well if you are ready to travel to Chennai, I have a Hsu Research VTF2 that I have been using with great satisfaction. It delivers low frequency with what a friend called 'fluidity / liquidity'. For example, in U-571, there is a scene where the sub is bombarded with multiple depth charges. The depth charges explode within micro seconds of each other. Most subs will mix the sounds into a rumble where you cannot differentiate between the explosions. The Hsu, on the other hand, delivers each explosion separately and distinctively, even when the time difference between the explosions are very very small. Similarly when there is a gun shot, the sound is deep and sharp with no resonance, rumble, or echo.
Hsu is going to be represented in India very shortly and will be available in the 50K range.
Manu, I am not sure what you are looking for. Instead of desperately looking for multiple subs, you should re-look at your whole set up. A set of four floor standing largish speakers with 8 inch woofers attached to, may be, two subs will give you much 'larger' sound overall with all the low frequency rumble that you are looking for. In addition, if you get active speakers, they will enhance the volume of sound that you are looking for.
All these propositions are expensive, and need very careful planning and execution. I would suggest you get a sound engineer to measure you room and make suggestions. If you spend a little money on your room acoustics, you will find vast improvements in sound. A bed cushion, though a cute idea, will not work as a good sound absorber or a sound diffuser. You need to use sound tiles that are available backed by glasswool that can actually absorb the sound well. In addition, if you set up proper bass traps, you low frequency sound will increase by at least 40 to 50%.
Cheers
