So what you are looking for is a machine with the absolute minimum of the following travels X10 Y6 and clearance under the Zaxis of at least 8" to clear the parts and the added height of the rotary axis. And a 4th axis to rotate the cylindrical parts. Plus you want .001" accuracy.
It will more than likely need to be X12 Y8 Z8 because you need a little room to get around the items.
http://www.taigtools.com/cmill.html. with a sherline 4th axis. If all you are doing is 6" round parts and less than 5.5" flat parts you will be all set.
On the round part all you really need to do is get to the middle of the part and stay there. The 4th axis rotates and the table will pretty much stay still.
As you will not have any cutting force to speak of, you won't need a cast iron machine.
I have a Taig and I can measure it if you are absolutly sure of the size of the parts you wan to make.
How much are you looking to spend. A ready to run machine will be about 2K usd plus,plus,plus.
Mike