Ships of the class
The Intrepid was a CGI model created at Eden FX that was essentially a kitbash, built by Pierre Drolet, rendered, animated and lit by Rob Bonchune from the John Eaves design based on the NX class model. Eaves went on to remark, "The armada drawings never went past the rough sketch form and after the producers made their choices the drawings went right to Eden to be built."  According to Bonchune, "any and all parts were pilfered if possible! Only way to get things done!" 
Regarding the lack of registry or name on the primary hull, Bonchune stated that "the model is kinda medium-lo quality as it was never built to get close, so it was built/textured accordingly. I also lit her very plainly so you could see the details."  More to the point, Bonchune said,"As for the "half saucer", we honestly have never called it anything else. Even our directory structures are called half saucer. We did not even catch that it was referred to as the Intrepid in an episode!"'. 
According to the novel Beneath the Raptor's Wing, this class of Earth starships was named the Intrepid class.