I think the ability to label each segment of a line, poly, plus getting the total measurement should be implmented into the ArcGIS for javascript API. I contacted tech support about this and this was there suggestion.
Our old arcims site did this, but i'm not a developer so i'm not for sure on how that worked. So our users went from being able to do this with arcims site, and then when we moved onto our custom application written in javascript they are unable to label segments when using measurement tools.
I understand this is possilbe in flex or silverlight.