OK, here's pretty much how my bag looked at WDW.
The lower left is a flap that is normally down. That's where the DSLR sits. Underneath is the remote shutter release, Clamperpod, and camel hair brush.
In the middle, there's the Pentax 50/200mm in the rear (sitting inside its inverted lens hood), the Zenitar 16mm fisheye, and underneath that, the Sigma 28mm.
On the right, there's the "kit" Pentax 18/55mm resting on top of the K1000 35mm camera, with no lens attached, just a body cap. (Yes, once a twice, something resting on top would trip the shutter - I tried to get into the habit of not winding the film on the last picture I took before putting it away.)
There's also a removable velcro/snaps film bag that I had attached to the bottom of the top cover. When I'm not shooting film, I leave it at home.
The front flap holds the filters, SD cards, batteries, and the quick-release for the big ball head, when it's not attached to a camera.
When closed up, it's not too big - there's a Dining Plan brochure for reference.
If I had a proper small scale, I'd weigh it. It's really not too awful, and the Op/Tech SOS strap helps a lot, too.
Once or twice, I carried a small miniDV camcorder in there, too - now THAT made it feel heavy!
I looked at a few newer bags but I couldn't find anything that could hold as much and take up so little space. It looks a little haphazard in the photo, but things are actually pretty secure and it'd take a heck of a bump to actually do any damage to anything inside. The whole thing can be zipped up, too, if I want to make it truly weather-resistant.