Unless you are buying used, I would stay away from anything in the 7k price range. 7k is on the lower end of construction boring machines and if you're worried about accuracy, you wont find it there.
If you are buying used, I would go with a Gannomat. They are on the upper end of machines and they last a long time. I know plenty of people that have Gannomat's and they are very happy with the durability and accuracy. The only problem with buying them used is that they are hard to find because people tend to keep a hold of them for a long time.
I would suggest a lease to buy option on a new machine though, if you can. If you have the demand, you'll find that doweling will really speed up production for you and you'll pay off that leased machine quickly. Plus, if you don't like that machine ultimately, you wont be stuck with it.
Whatever you do though, don't go cheap. Remember, this machine is making you money so durability and accuracy are key. If you get into production with a cheap machine you are rolling the dice. It might work great, but it has an equal chance to break down on you and if it does, it will take time to fix it. It costs less to spend a couple thousand more on a good machine then to have a bad one break and not be able to get jobs out the door for days.
Good luck and I hope you find what you're looking for.