The Pen EP-7 is the same size as the older EP-5. With any of the Olympus prime lenses, it's about as small as you get (ignoring the Pentax Q, which was ridiculously tiny).

But 100% agree on the OM-1 and OM-3. They're smaller than many APS-C bodies, especially once you add a lens, but they're nowhere near pocketable, not even in a jacket pocket. And I feel like the OM-3 was a bit of a miss - it should have been a "rangefinder" form factor (no pentaprism hump) and a few mm smaller in each dimension. And marketed as a Pen-F. That said, the camera itself seems to be pretty darn good - basically a slightly smaller, vintage-vibe OM-1. Once used examples hit the market, I'll be tempted to buy one.

My parents both shoot Nikon DSLRs and I chuckle every time they break out their birding lenses (400mm NIKKOR of some sort). It's as big as my forearm and fills half a backpack. My Lumix 100-300 (yeah, not quite apple-to-apple) is minuscule in comparison. [I don't do enough wildlife to bother with a more expensive telephoto).