Before I answer, someone on the Mongoose boards has posted
pics of an early prototype mini. (The current version, which has been re-purposed into the D6, doesn't have that grille in front of the deckhouse.)
I wouldn't mind that material used to represent cloaked versions of the ships, actually...
Okay, now back to the question.
Right now,
SFB's entry into the e23 scene is still in its relative infancy; unlike
FC and
Starmada, there's probably not enough available yet in pdf form in order to get up and running again. There is the
Electronic Master Rulebook, yes; but arguably it's more useful alongside the ink-and-paper material out there than anything.
FC, on the other hand, has a more concrete presence online. The
Reference Rulebook incorporates the Main Era rules available at the moment; there are a fair few colour Ship Card packs on the site (though you can find black-and-white versions of many of the cards in the free-to-access
Commander's Circle); plus you can go into the Middle Years online, as the various
rules and ships from
Briefing #2 are also up. (The Middle Years ships come 12 to a pack, so cost twice as much as the six-ship-per-pack Main Era files.)
Also, if you feel like trying out something a little different, there is the
Omega Playtest Rulebook... written in part by yours truly (though owing far more to the outstanding graphical work put in by Richard Smith).
EDIT:
Andorians!