Mark,
I'm not familiar with TestStand but with the instruments how much detail are you hoping to log per instrument that is used. One thing you could do is possibly always log the results of a "*idn?" query (or a similar query) when every instrument is initialized.
By putting this "logging" into the initialization you can build this into a step and keep it transparent to the test developer. If you're all using instrument drivers to communicate with the instruments then maybe making the change in the drivers themselves would be the best option since that wouldn't effect the test developers.
Just an idea.
Kamran