> Unfortunately, the traceback.py module reads from files to load the source lines for the traceback (using linecache.py).

linecache is supposed to cache the result. When all files generating tracebacks of your project are cached, only os.stat() is called on each file to check if the file has been modified.

But I'm not sure I understood your request: do you want the line content in your traceback or not? If you don't want the line content, the traceback module should be modified to add an option "don't read file content".