I travel to Dhaka a couple of times a year. I have gone several ways and Dragonair through HKG is by far the best way to handle that long trip. I usually overnight at NRT and then head on down the next morning to HKG and on to DAC arriving at about 9PM.
I try to use Cathay for as many of the segments as possible as CP is far better in my opinion than AA or JL.

You can also connect in DEL on Jet Airways but it is a nasty layover in DEL.

Good Luck!