You could look at Delta back through JFK. This way you get the completely flat bed on the 767 product they offer on this route (on most services). Downside is the long connection but might be more comfortable. Could still go out through ATL? Or you can also look at using KLM and going through AMS in 1 direction and using DL the other.
Just a thought – can always talk to an agent if offering not coming up online.
Otherwise the new 77W on AA from DFW looks very good and would be tempted to use that though the hassle of going through Heathrow.