No need to get crazy about how many times you've played, lots of us arent bragging about how much time i've spent playing campaign alone. I dont know how proud of that any of us should be, aside from the developers.
anyways, to the OP, Brutes shouldnt appear in Reach. as far as my understanding of the Canon goes, the brutes are at the time of reach being punished for starting the war with humans pre-emptively. Also, the brutes dont really take military strength (with fully functional ships, weapons, and shielded armor) until the elites "fail" at protecting the prophet thats killed in halo 2. This is when the prophets deem the elites unfit and forcefully remove them from the covenant, the brutes taking their place.
Also, i think the first spartan encounter with brutes was on the unyielding heirophant (uneven elephant or w.e :p ). there appears to be very little to no data on them before this time, other than the first encounter at harvest.
In the novel The fall of reach, there were also no brutes encountered or even mentioned.
I could be wrong though, Brutes may appear. Its Bungie's game and they can do whatever they want with it. i'll just be happy to play it for whatever many more hours of my life. They know the formula for a decent game and i trust them to come through, even if i gotta kill a few retarded monkies in the process.