The article cited by gfretwell (680.22 (C)) actually pertains to "II. Permanently Installed Pools", which is a section separate from "IV. Spas and Hot Tubs." The closest the NEC comes to stating a required distance for the disconnect, aside from the "readily accessible and within sight" requirement in 680.12, is the 5' required for an "Emergency Switch" in 680.41; but this "emergency switch" is not the same as the "maintenance disconnect," AND the article concludes with the statement that "This requiremnet shall NOT apply to single-family dwellings."
So to summarize, all we get from the NEC, regarding home hot tubs, is "readily accessible and within sight." For more specifics you need to talk to your AHJ.