Our workflow is such that developers do not work directly off of "trunk", but rather copy the trunk to private branches which they then modify to complete their assign tasks. After code review the changes are then merged into trunk and an official build is done.
I don't see any easy way to utilize the Personal Build feature effectively using our current model. The system assumes that everyone is using the same codebase which, the way we have it set up, is not the case. If there was a way to specify a property/variable when defining the VCS roots then it would be able to dynamically refer to a developer's branch in order to determine the changed files.
The build procedure for our product is quite complex so it would be a huge win if we could leverage the power of TC during the development smoke test phase to get as close to an official build as possible.