Anthony,
To the best of my knowledge, no one makes an X-302 model as yet. In fact, there are only 4 SG-1 models that I've seen commercially produced: A Cargo ship, Death Glider, Gate itself, and a Zat Gun. All of these are resin kits produced by WARP models in the UK. They are all
extremely expensive!
As for line / technical / blueprint drawings, you're going to have a problem here as well. I'm pretty sure that all of the ships on SG-1 are computer generated and unless someone has taken the time to develop their own drawings, they're just not available. The CAD versions of the ships are not available to the public because SG-1 is still in production. Your only real option is to use DVD captures to scratchbuild your own version.
Sorry I couldn't be of more help...