Yeah I had something similar last night. Currently I am playing on a medium map. The Torians were picking on my allies so I declared war on them. They sent me the usual snoty reply that they were going to feed me to their giant microwave or something of the sort. At the time I had 4-5 small corvettes sitting around with only Laser II on them. I had been out researching everyone for a long time (double the nearest races research) and had my economy maxed (10,000bc save and earning about 300bc a turn in excess). I started building some fighter mkIs (2 laser IV, 2 impulse III engines) on every planet. In about 10 weeks I had something like 20 fighter mkI and was doing some research into more advance play things of destruction.
They started throwing transports at me like they were going out of style and I knocked them all out of the sky (I think I counted 12 transports in 4 weeks that they sent at me, mostly unescorted). Their little blitzkrieg of invasion failed. Their closest planet didn't have any orbital defense so I rolled right over it despite my little 6hp fighters (swarming). Invaded and took it over. I then proceeded to produce some frigates after researching to plasma I weapons, point defense, and medium hulls. This was about 4-5 turns after taking the nearest planet of the Torians. I then buitl about a half dozen of them each with 1 point defense, 4 plasma I cannons and 2 warp drives (oh yeah, I researched those as well). I had some bad mamba jambas punching out 6 energy damage, absorbing 2 missile damage, and moving 6 pc a turn (with 16hp). The Torians were using missile weapons and missile defense. I rolled right over 3 more planets carving off about a third of their little empire in the upper left hand corner (I had siezed the lower left from the Drengi about a half year before and I started in the middle). I then sued for peace and they backed down off their little war with a vengence.
Of course like 2 turns before suing for peace the Achreons delcared war on me because I was attacking their pitiful little friends. They of course won't settle for peace. Right before saving and calling it a night I had 40 fighter I's, 8 frigate II's (with the plasma weapons etc, the earlier ones only had 5 laser V making them 1 attack less), and 3-4 recon fighter mkI (similar to the fighter I's, but with maxed sensors and no weapons) for pathfinding (no I have not researched eyes of the universe yet) all headed toward them. I don't share a boarder with them and it is going to take 2-3 weeks to get there, even with 4 and 6 pc a week travel speeds. Oh yeah, that is only about 2/3rd of my fleet. The rest is hanging back as a temporary reserve. I intend to reduce my numbers to 2-3 frigates and maybe a half dozen fighter mkII (upgrade them with some plasma III weapons once those are done being researched) for my peace time fleet.
I figure this evening I will teach them a little lesson before asking for peace. The fun thing is despite the military force I am still brining in positive amounts of money and have about 6,000bc in my treasury (would have more, but I had to buy a couple of transports for some quick invasions of the Torians, all other warships were built instead of bought). I think last I checked I had started with the smallest navy after demobilizing following the Drengi conquest and had the largest navy in 10 turns (previously the Torians had it). I have the largest military, economy, and research by a factor of about 2:1 compared to the next largest entity (still the Torians).
I should enjoy this 'smack down' tonight. Then I will probably go for a diplomatic victory.
-Matt