People keep asking for 'backstory' to make the game more interesting. Personally, I'm against backstory because it makes the game LESS customizable and adaptable to any play style. BUT... we could possibly have little fragments of backstory rather than an 'over-all' theme that might restrict the game.
How about a space monster that protects a NEUTRAL race? It could be something that lives in the system sun, or in a storm in the system. It attacks any ship that doesn't have a special device on it, and the device is a racial tech restricted to the neutrals.

The neutrals could have a 'religious' awe of the beast and turn out to support it when it goes into combat against your ships. It's their "god" after all. If you are fighting with it, they are darn well gonna help it out. This would help solve the problem of neutrals being too wimpy, also.
That and a classic "Master of Orion" type guardian standing over an empty ring/sphere world are the two best ways to add non-random space monsters to the game.
RANDOM space monsters are easy. Create some graphics of monsters and treat them as ships. Have a folder called "monsters" with the graphics and a full set of AI files just like a race. The game would then use those files to design a monster when a random monster event was called for. Only a few 'special' settings would be needed for the monsters.
[This message has been edited by Baron Munchausen (edited 20 May 2001).]