I don't have the deepest understanding of the CLI runtime, but here a few issues I can see.

The runtime is language-agnostic. So you would have to make it work at the CLI level in a language-agnostic manner.

You may not have source for some parts of the callstack.

There are an absurd number of transitions going from source to executable. Code generation can happen at build-time, link-time, install-time, load-time, and runtime during hotspot analysis.

But on the flipside any exceptions on an aspx page or debug time exceptions come with line numbers, so at some level it is possible.

To show line numbers in the stack trace, the code has to be compiled with that feature enabled.

Unfortunately, I can't recall offhand what the necessary compiler settings are (perhaps "debug" or "stacktrace"?).

There's a list of compiler options: http://msdn2.microsoft.com/en-us/library/6ds95cz0(VS.80).aspx

Here is an article that discusses how to get line number for an exception stack trace.
http://dnchannel.blogspot.com/2007/09/getting-line-numbers-in-exception-stack.html