Just got back from an event shoot today and pulled out all the stuff in the bag and snapped a photo of it. The bag is a ThinkTank Retrospective 20, which I got to replace a Domke J-2 and to complement a Domke F-3X, mainly for the times that I'm shooting with a 70-200 f/2.8 lens. I could have shoved more stuff into the bag, such as a UWA or a macro lens, battery chargers, flash triggers, cleaning supplies, etc. But since it was an all-day shoot I packed relatively light.
Regarding your criteria:
1) Padding is alright, think enough to protect from bumps while it's on your shoulder, but might not be enough to really pad from a fall. This is more of a shooter's bag than a storage bag. I prefer this padding over that in the Crumplers and the Domke J-2, which are all too thick and get in the way of lens swaps while shooting.
2) Yes, the TTR 10, 20 and 30 all look like normal messenger bags in either Pinestone or black.
3) The front compartment is large enough to hold a pro body and more, so if you're going for maximum storage capacity, you could put the body there, fit three large lenses (more if you stack them vertically) in the three lens columns, and stick two flashes in the inner compartments on the two ends. If you need even more space you can add on two more lens pouches on the loops at the ends.
4) I've stuck a monopod under the top flap with no problems. Some people stick one tripod leg into the end-loops as well. There are no proper tripod straps on this bag, since it was designed not to look like a camera bag.
5) The TTR will accomodate a 70-200 stored vertically. I've read that it can fit a camera mounted onto a 70-200. However, since I planned to be doing a lot of that, I went for the TTR20 instead. No problems whatsoever, and I can drop the camera with a 70-200 mounted into the bag at the end of the day without having to switch lenses around to get the gear to fit. The TTR20 is a couple of inches taller than the 10, and I like having that extra room so nothing has to be forced about.
6) TTR is comfortable worn on one shoulder or slung across the body. Both ways, it's easy to access your gear, whether you have it kept in the main compartment or in separate pouches on the ends.
7) There is a back pocket to keep notebooks, maps and other documents. There is a huge front pocket to dump a lunch box, spare clothing, etc. There are a couple of inner compartments that have pen slots, business card slots, and a lanyard with a clip which I use to secure my memory card pouch. I got a Lowepro bottle pouch to hold my water bottle, or any other small item I need quick access to.
8) The strap on this bag is super thick and it has a huge piece of padding which has jelly strips so it won't slip. Not as supple as the Domke straps but just as wide, so just as comfortable. Don't overload it and you'll be fine.
9) It has an all-weather which will shield the bag from the elements, although I've never deployed it before.
One last thing, I bought a Outdoor Research sternum strap so the bag wouldn't slide around while I was cycling, and found that it makes the bag more comfortable to walk around with as well. Something to consider for all messenger-style bags.