andyy I'm probably being a bit dim but i think most of us would prefer 4 engines to 2 for a LRMPA and I think we'd accept that there should be good endurance & good low level performance.
Agree 2 engines for LRMPA seems to have disadvantages. Although the french (Atlantique) and US (P7) seem to be ok with it. The concept above has 3 engines btw. A small turbofan for take-off and redunancy. And if high performance is required.
could this kit not be fitted into Hercules airframes?
It seems to me the Hercules and A400M even more are out of the picture in terms of size and operating costs. Both aircraft are optimized for maindeck cargo height and therefor have marginal options for lower decks/ bays.. They are inherent bulky, not lean and mean..
http://www.eol.ucar.edu/raf/pics/C-130_xsctn.gif