Don't want to be a party pooper, but I never saw the reason for having detailed stack traces. Tests should fail for exactly one reason. If you have a bunch of entirely different checks in your test case and struggle to find out what exactly failed, there's something wrong. Better split them up in seperate tests.
I am still on DUnit and have never really used DUnitX, but can't you debug a test? That should easily tell you what, and where something is going wrong. The fabulous "Test Insight" plugin from Stefan allows you to directly debug the test at your cursor position with [Alt]+[F9]
sglienke / TestInsight / wiki / Home — Bitbucket