There is a definite tone I see when shooting with the E-1, particularly skin tones. Luckily, I really like the tones from the E-1. They appear slightly less saturated than the tones I see when shooting film (accepting that film development variances are probably greater than digital variances - try taking a portrait with Velvia 50 and you will know when you've been Tangoed
). An example is a shot of my son I posted earlier (
http://www.photocamel.com/index.php/topic,2056.0.html). I'm pretty sure that if this came from a film camera and developed in the usual 1 hour lab it would appear more saturated.
I doubt if I'd be able to spot different digital cameras based on an example shot - it should be easier to spot which film was used though, and I'm sure there are people who can do this with great accuracy.