There isn't. That's the problem. You can deflect all you please, but NEVER should ten CRAP SHIPS that you can build in the first 30 seconds of the game be able to bring down a HEAVILY defended planet system.
With standard game speed and resource settings, it takes a bare minimum of three and a half minutes *just* to get the mere capability of building siege frigs if you go straight for them at the cost of all else. It then takes 45 seconds to build each one, and that's if you have the resources to do so (If you dropped everything, you won't).
In order to finance a seige rush, you'll at least need to get your flagship up and send it out hunting so you can get additional mines up on other planets. That will delay the initial availability of sieges a fair amount (not enough crystal to do both, and one mine gives you a pretty sad trickle).
Financing aside (and that's a big aside), it will take you seven and a half minutes to build ten seige frigs. For the cost of an extra frig factory (built while researching Krosovs) you can halve that... but that puts the total cost past 10000 credits and 1000 crystal, which is a very difficult price to ignore early-game.
For less money than that, a bit more metal, and a LOT less crystal (crystal being a big limiting factor early game), you could make TWENTY cobalts in less time, and have a strong fleet for creeping and colonizing to boot. By the time the siege player is ready, you'll have multiple colonies with resources rolling in, gained at least a couple of levels on your flagship, AND have a fleet strong enough to rip his to bits and be in shape to crush his homeworld shortly thereafter (regardless the status of your own capital).
It's all a matter of strategy. Siege rushes may be powerful against an unprepared player, but they're a huge gamble and are hardly unstoppable. Much like rushes in other games, a failed rush attempt pretty much guarantees your own loss against a competent enemy.
So let me make this clear kyro, you
don't actually want epic fleet battles between frigates, cruisers, and capital ships with lasers and missiles dancing across space in a symphony of destruction? Instead, you want a zergling rush ala 1995 where each side spams a crap fleet at the start of the game (the first 10 minutes is certainly the start of a 4x game) and rushes each others capital planet?
If I wanted StarCraft, I'd go buy it. Remember your roots and your fan base, SD is known for its deep gameplay that builds to a crescendo as the game progresses. Where losing systems actually mean something. Not musical chairs.
Did I mention that it's impossible to "lose" with a siege rush against a capital? Try it some time. You nuke the cap, the alligence falls. The alligence falls, the income is paralyzed. When that happens you lose, even if you killed all their siege frigs.