Full Thrust, as a line, has both vehicle (in Dirtside II) and ship design rules (In FT and FB1) that are not too far off from travelleresque... but note: the Power Projection rules scale very differently than do the implied sizes from the FT line...
1 FT Mass unit is 100 Tons metric; that's about 10 Td for warships, and closer to 40T for empty freighters. Average hulls get 1 hit per 3.3 Mass (30% of mass to hull structure, and 1 hit per mass of hull structure allocation). At 1hit per 3.3 mass rate, the 1 hit per 500Td of Power Projection works out to be 1 mass per 150 Td...
And just for total obnoxiousness, 1 mass of Cargo space is "50CS"
The CS requirements for various elements are summarised below:
Class 5 vehicle (less crew) 20 CS
Class 4 vehicle “ “ 16 CS
Class 3 vehicle “ “ 12 CS
Class 2 vehicle “ “ 8 CS
Class 1 vehicle “ “ 4 CS
One man (normal accommodation) 4 CS
One man in Cryosleep 1 CS
This meshes pretty damned well to Traveller... at 0.5Td per CS... using Double Occupancy staterooms for troops, and half-ton low-berths. It also unfortunately puts size 5 vehicles at a mere 10Td. One could argue it up to 1CS=1Td; that makes a mass 50Td and a scoutship a mere 2mass... and any hit obliterates it, including quite possibly a point defense.
Using FT as a design system for Traveller has one big drawback: their jump system comes in one size only. Assuming 1 mass = 25Td, we get a mass 4 minimum for jump...
Hull Costs
Pt MU
04
00 mass 4 hull
02
01 Weak Hull 1 hit
02
01 Jump Drive (oversized due to minimum size)
02
01 Maneuver Drive (Thrust 5 - minimum size drive)
00 01 Cargo (50CS)
Alternatively, a size 4 non-jump ship can mount (for 7 points more) a size 1 battery and a fire control...
One could easily use Traveller for running the FT universe, but note that biggest ships in the FTU are under 300 Mass... Even at 50Td/Mass, that's still well smaller than the OTU... a mere 15000Td... (Even at the implied Power Projection conversion of 1=150, it's still well under the OTU'... at 45,000Td.)