I've found this forum to be very, uh, interesting to follow. Really though, there are a lot of knowledge and even more experience here. Sometimes you have to wade through a lot of opinions, but all is good.
There are a lot of people out there making kits - some on the more "original" side and some not. Check out a book called "The complete guide to cobra replicas" It is again a book of opinions, but it does offer up a lot of solid starter advice.
www.cobracountry.com used to be the website, but I can't seem to bring it up now.
Lone star and Factory Five Racing use a "donor" car to provide most of the parts. This is a good option for a low dollar boneyard special that will allow you the comfort of having most of the parts in one spot.
For more "customized" kits, there are a bunch of mfr's out there that do pretty much whatever you can dream up. Of course the higher you dream, the lighter your pocket is.
Good luck! Take it from one bitten since age 16! (now 35 and finally getting started.....uuuuggggh)