A useful site giving visual representations of the size of many SF vehicles.
Useful for me since my "fighter shuttle" size in my 4X game turns out to be a nice match for a Boeing 747 - just the size of the Orion Shuttle. Which means, yes, most SF starfighters are G-class units (the equivalent of a grav tank or atmospheric vehicle). [H-class is human by the way. The largest class of "ship" is the A-class Assault vessels (a Dreadnaught by any other name would still cure constipation in an enemy), although star bases and battlestations can go to Z-class and above. Unfortunately I don't quite make P-class = planet, although S-class may make a star...]
Fantasy Flight Games' Rogue Trader contains an interesting mechanic in their character generation system called The Origin Path. This is a single page grid in which are arranged various character options. Each row is a specific class of options marking the progression of the character to the status of Rogue Trader, and the totality forms a kind of life path generator.
What I found particularly interesting is that the rows not only includes the things you might expect from a lifepath generator, such as the character's homeworld and final career, but also include such aspects as the character's various motivations. The rows are, from top to bottom, Homeworld (the type of world the character hails from), Birthright (the character's upbringing in the Imperial culture), Lure of the Void (why the character ventured into space), Trials and Travails (essentially the character's past experience), Motivation (what drives the character), and finally Career (the character's role as a Rogue Trader).
Ideally the player should start at the top or bottom (although I feel that starting anywhere you like is just as justified), and the proceed down or up the grid. Each time they do so, they may either remain in the same column, or move one column to the left or right. This constraint tends to forge an appropriate character simply and easily, with the result easily visible to the player.
It definitely seems like it might be applicable to other class-based games, such as D&D, in order to generate a simple history of how the player became a hero, that is culturally relevant to the campaign background, without inundating the players with information (and option) overload.