I think you might be wrong about that.
Shadow mapping for the flash light was added to the update that came with EP2 - Much before L4D.
Isn't Half-Life baking the shadows? I don't call that shadows(real-time). L4D had
pretty shadows where EP2 wasn't that good for me. I think I can say Source was incomplete by that time. But I also know about the troubles they got into. EP2 is when it came near completion and L4D was the polished and finished engine I want to see.
I wonder if I can get some updates to Dark Messiah too.
Edit: Maybe I'm too harsh on source. But CS ran pretty bad on my Pentium D. Although new updates might have changed it. As it can run on MAC now. That should count as something.
Some screens, I really searched hard to find a pretty flashlight image for HL2:EP2. I will take my owns.
http://img692.imageshack.us/img692/4598/22419128.png
http://www.cheats.ru/uploaded/h/halflife2episode2/halflife2episode2-02475.jpg
http://i106.photobucket.com/albums/m261/coolcorky/c2m3_coaster0000.jpg
http://img145.imageshack.us/img145/1687/softshadowsjw4.jpg
This is personal opinion though as all of my posts.