W.r.t. armor, my primary question is: what is the right level of robustness for a civilian design? This has one more ton of armor than the KR-61 (which seems to be the least armored design in TR3057). Since the SI is only 2 though, it ends up being similar in terms of the scale of a survivable accident. Yeah, it makes sense.
If this is a civilian design, the low armor makes plenty of sense.
More generally, a modified Spacebus could _be_ the cargo. For example, you could easily fit 30 steerage quarters + 10 tons of supplies for transportable living quarters with a 2 month supply anywhere needed in space. It's a bit expensive compared to some other options, but the transportability is quite nice.
Now I'm imagining a Mule, Mammoth, or Behemoth Dropship with a mess of Small Craft Bays, whose only job is carry a massive number of Small Craft like this on a single Docking Collar. You can drop them all off without worrying about passenger movement (since the passengers would be kept in their Small Craft), and the Dropship can perform basic maintenance in orbit. The key is that it would need either a space station to transfer the people to, or some other way for the passengers to get to the planet's surface. (two more Small Craft designs, with 3/5 thrust, one with a cargo capacity of ~120 tons and the other with a passenger compartment? The cargo one will need 2 trips to transfer cargo from the SpaceBus to the surface, while the passenger version will have less Life Support since it will only travel from orbit to surface when it is safe)
Rough guide (all data from MML 0.48.0):
* Mule (gains 39 SC capacity): 2 bays @ 2715 capacity + 1 bay @ 2714.5 tons capacity -> 2 bays @ 13 Small Craft & 115 tons cargo + 1 bay @ 13 Small Craft Bays & 114.5 tons cargo
* Mammoth (gains 185 Small Craft): 5 bays @ 7563 tons cargo capacity -> 5 bays @ 37 Small Craft & 163 tons cargo capacity (existing 4 Small Craft were not touched)
* Behemoth: (gains 372 Small Craft): 2 bays @ 18780 tons cargo capacity + 2 bays @ 18779.5 tons cargo capacity -> 2 bays @ 93 Small Craft & 180 tons cargo capacity + 2 bays @ 93 Small Craft & 179.5 tons cargo capacity (existing 20 Small Craft were not touched)
So you lose the ability to carry any single item over 123 tons, but you can deliver it to any point on a planet without needing to stop at a Spaceport first. You also save the time of transshipping the cargo onto a Dropship, as cargo can be moved onto all of the Small Craft simultaneously. Good for colonies with low levels of ground transportation ability, and fast turn-around of materials.
The problem becomes that a regular cargo Mule can carry 8.2 kilotons of cargo and costs ~163.3 million C-Bills. A Beehive Mule by itself would cost 212.4 million C-Bills, 39 Cargo Small craft is an additional 181.8 million C-Bills, for a total of 394.2 million C-Bills. The Beehive would only be able to carry ~6.5 kilotons of cargo (38*160+1*123+2*115+1*114.5).
So the Mule has a ratio of ~20k:1 in terms of C-Bill cost vs tons carried, while a Beehive is ~60k:1 in terms of C-Bills cost per ton carried. So for triple the shipping price in order to get cargo faster and delivered on-site, this would be useful.
LaGrange is designing a pallet jack, not a jump point to planet shuttle... 
Jump point to planet is about 10 days (using Sol - Terra as the base). I was thinking 5 days of Life Support in case something terrible happens while transferring from planetary orbit to lunar orbit or even LaGrange point distance. You are right, reducing it to 2 days Life Support would make the 20-person setup take up 7 tons instead of 10, meaning that you go from fitting in 16 groups of 20 people to fitting 22 sets of 20 people at a time, with 6 tons of cargo still available.
