The KD550 and 650 came with arms. They look like decent med mass arms but I don't have much experience with them. There are also a couple of less expensive ones with that base material. One is the 5070 I believe. It might have auto functions. I have a KD500. At the moment I have an Alphason 100S on there. I also have a 770D which is a nice table w/arm, but I had to modify the wood base.
I guess you can tell that I'm a DD freak. I used to have a Goldmund Studietto/Zeta. Anyway Kenwoods are pretty cheap and have great potential. If you find a 550 or 650 and don't like the arm, just put something else on there.