Never had any experience with DDR of MT, but I'm sure if you do a search here, you might find something. Try using the google funtion in the top right corner.
As far as what you are looking for, you are probably on the right path. If you aren't going to reload, I would plan on buying high-end ammo (HSM, Gunwerks, etc). In the end, you would save a bunch of money getting in to reloading and it is really pretty simple once you get going. It is fairly expensive up front, but it will save you a bunch in the long run. Either way, if you are going to build a rifle, you will want to pick one of those loads to build off of if you aren't going to reload.
One other suggestion as far as guns go is to watch the classifieds on here. There are a ton of custom rifles
that go up for sale daily. You will save a bunch of money that way and might be able to back in to a rifle that you thought would be out of your budget.
Once you get the rifle and loads, you can then work on building a scope that is customized to your rifle. You can order a Huskema or Gunwerks scope for it, or just get a basic scope and order Kenton turrets for it.
Good luck and welcome to the addiction!