E-P1 Dynamic Range compared to 'pro' cameras

Apologies for what may be a rather novice question, but I've been wondering for a while now just how the E-P1 compares to cameras with bigger sensors like the D300 (to name just one) in regards to the Dynamic Range it can capture?

I often find that I'm pushing my E-P1 to its limits when trying to capture deep shadows and bright skies, and I realise that this may be impossible with any camera, but I want to know just how much more Dynamic Range (DR) I could be getting with a higher-spec camera.

Or am I really just asking something impossible of photography?

Thanks in advance.

(P.S. I am aware of HDR pictures, but am not interested in them in this particular thread).

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