In this book there are several drawings of projects/studies around Boeing 707 design.
http://www.amazon.com/Boeing-707-Pioneer-Jetliner-History/dp/0760306753/ref=sr_1_1?ie=UTF8&qid=1385264660&sr=8-1&keywords=boeing+707
pg 20
- Similar to B-47: 2 jet double pods and shoulder mounted swept wings.
pg 22
- Boeing model 473. Idem first one in pg 20, but only 2 engines
- Boeing model 473-25. Idem first one in pg 20, but 6 engines: 4 jet pods 2 single inboard and 2 double outboard
pg 23
- Boeing model 473-47. Idem first one in pg 20, but low wings and only 2 engines. Smilar to Boeing 737 but straight tail surfaces and moderately swept wings.
pg 25
- Boeing model 707-6. Low wings 2 jet double pods. Very close to 367-80 (dash 80)
pg 28
- Boeing 707-7-27 like dash 80 but with 4 turboprops and wing tip tanks
- Boeing 707-7-39 like dash 80 but with 6 engines: 4 jet pods 2 single outboard and 2 double inboard, and wing tip tanks
pg 58
- Boeing 707-020 Shortened version with only 2 engines
pg 75
- Boeing 707-320-101 Double deck large-capasity (up to 250 passengers) version
Sorry, I have no scanner currently
