>I note that some NET luminaries don't seem to use the typed dataset's change tracking, preferring to roll their own. Presumably there's more to it. I have a feeling that some people handle change tracking in a SP(!) i.e. pass everything to the backend and let it handle it, but lets wait and see...

Hi John,

There's also the "data shadowing" concept, which would involve a copy of the original data associated with an object. The (biz) object, upon saving changes, could easily detect and promote only the values/fields changed in its editing session, by comparing them with its original data shadow. In other words, the change tracking would be central to the (biz) object class.
I don't develop in .NET currently. This is something we use in our VFP framework, though I assume it would apply to any disconnected scenario.