ok,looking to set up a new AR15,as close to an M4 style setup as possible.basically,minus the burst setting,and 16" bbl overall,not 14.5". i want flattop,and a standard rail system, so preferably one that comes from the factory with that as an optional upgrade,for simplicity's sake. if not,no big deal. i'd prefer 6 position collapsible buttstock,but 4 will suffice if necessary. i want to try to keep everything stock,as far as the basic rifle and rails go. so,suggestions? i prefer bushmaster and dpms,but i'm open to suggestion.i'd like to,if possible,keep the rifle/rails under $1000,and the better the deal,the happier i'll be.Price ranges and models would be much appreciated.Thanks in advance.

RRA from Eaglefireams.net.  I've got an entry tactical and like it a lot.  If I had to do it again, I'd get a UTE 2 and save some bucks.  I've got an EoTech and really like that lil' thing.  Prices are on the site.
www.eaglefirearms.net/Rock%20River%20Arms%20Rifles.htm

Jake