We do at our research group.
Our in-house finite element code is basically a collection of routines that support our research. It is written in pascal, and amounts to more than 4 MB.
bash-3.00$ find * -name *.[ph] | xargs wc < A lot of details on the files which I excluded > 151697 477333 4483697 total
Of course, I am not able to oversee everything, so I expect some redundancy.
Regards,
Marten Jan