your desire for discs and dual susp. in that price range is going to bring your components so low you might not enjoy riding it so much, really only be a step up from wal mart. discs are not needed for mild trail running and rear susp. is going to bob and bounce alot. rim brakes will outperform the low quality discs you'll get anyway. i would urge you to take a good frameset and a bump to midrange components over the desire to have what will be poor discs and bad components. for about $4-500 you can get a great entry level hardtail that will perform well and hold up to some riding, then upgrade as you go along.
i can understand not wanting to over spend,, but at the same time you want to get a good bang for your buck. the kind of money your spending also look at iron horse, specialized, giant, gary fisher and i'm sure a couple others.