You can get away with a single 1k stone and the result will be a very "bitey" edge. Think of it like a saw with tiny teeth. The higher grit stone (like a 5k) would refine those teeth to make an edge which will slice more cleanly while keeping a nice bite from the 1k stone.
A lot of folks here like the Arashiyama stones, and really I don't think there would be any issues with using them. In fact there is a two stone set with them, a 1k and a 6k, which would fit the bill: http://www.chefknivestogo.com/4pcshstset.html
You will want a plate to flatten the stone with, and some suggest flattening every time while others would suggest doing it when the dishing is noticeable. It kind of depends on the person in that respect.
If you absolutely want one stone though, have a look at the Imanishi two sided stone (1k/6k): http://www.chefknivestogo.com/imtwosi1kst.html
This one stone gives you the 1k for sharpening and the 6k for refining.
I might also suggest this strop kit as well if you go that route: http://www.chefknivestogo.com/stsetwiunhob.html
It includes a flattening plate, stone holder, and strops to get you well on your way. Stropping is just a way to even further refine the edge and can function like a knife steel for harder Japanese knives. Plus it is an inexpensive way to give your edges some extra care and keep them in top condition.
Then just visit this page for compounds/sprays for the balsa strop (you don't need it for the leather strop unless you want it to work faster) and even other 3" x 8" strops: http://www.chefknivestogo.com/strops.html
Horse butt and kangaroo seem to be pretty popular, but I have always gotten good results from good ol' cowhide. lol
I personally have been getting good results going from a 1k straight to my strops loaded with a compound to refine the edge (I use four strops, two balsa and two leather), but again different people will have different opinions. The real key is in finding a method you like and that works for you.