I saw this idea come up in the Academy, but thought it totally deserved its own thread.
I'd love a stand-alone designer. It'd include all the techs, and would let you design every part and build ships from said parts but without the rest of the game.
This would be great for a couple of reasons.
First, it'd let people at least toy around with designs even if they're not on a computer with a tall enough screen to play, for example on their lap-top at work/school.
Second, it'd let people design things from scratch without needing to research every part first. That way you'll never get done researching that new engine only to find it doesn't suit your needs. The stand-alone designer would let you see the stats of a ship with that engine without having to research it all.
It shouldn't be hard to make, at least if there's a big compendium somewhere of all the techs and the formulas for calculating stats. I could probably make it myself if someone can point me toward those resources.
Edit: Wow, hive-mind. Looks like at least 3 other people had this same idea since I started typing this.