The first design, 473-12 reminds me of the Baade 152 The flying wing version is cool, too. Too bad we ended up with boring tubes with wings.
Interesting tidbit I just came across: the RAAF for 6 B707-320C aircraft including a boom refuelling system suitable to support F-111s. They were also pushing the 707s as a C-130A replacement. Could be an interesting subtle whiff: a RAAF 707 but with added boom: