I'm also looking for a finishing hone for touch-ups myself, and one helpful member here suggested I buy a Chinese 12k from Woodcraft - only $20 plus shipping, and more than adequate for touch-ups.

Check out the wiki too, it tells you just what hones you need, what various common types of hone are used for (1k, 4k, 8k, 12k etc), as well as how to lap and use a hone properly.