1. the 40 foot "NOVA 2"... with a cluster of 5 SSME's on the second stage (which is a non-starter).
2. same but with STME's (throw-away slightly souped up but lower ISP NLS version of SSME).
3. 42 foot diameter NOVA 2-- all F-1A's and J-2S's...
4. 42 footer with SSME's (still won't work).
5. 42 footer with STME's (since the STME's were never built but died with the NLS program, we'll assume that they would design them from the get-go to be air-startable and restartable...
6. The "variable diameter option"... Looks cooler, like a chubby version of Saturn V (not those graceful steps like Saturn V from the 13.5 foot CM to the 21.6 foot S-IVB to the 33 foot S-II/S-IC, but at least it's not a straight tube like the others... but seriously, WHY BOTHER with the different diameters when you're only going from 38 foot up to 42 foot to 46 foot with a 50 foot skirt over the F-1A's on the first stage?? Changing diameters costs money in tooling-- common diameter, while visually boring, saves a TON of money through common tooling to manufacture the stages...
7. Same thing but with SSME's... (STILL won't work...
)
8. Same thing but with STME's... (like I said, we'll assume they designed STME for airstarts...)
9. FLO piloted CRV lander vs. Apollo LM...
10. Nose cone/payload shrouds for the big hab lander/CRV...