If the zips were a little longer you'd be able to fit a FF body without a lens attached into the zipped up pockets. A 100D with no lens on or an advanced compact will fit into the pockets in front of those just fine.
If not for the protruding part of the viewfinder bump for the flash on my 500D, it would go into either of the pockets just fine.
I dunno if the smaller jacket sizes have smaller pockets, though I imagine that in terms of the largest pockets they might.
The zipped pockets accommodate my 17-85mm with a lot of room to spare, so it should easily fit the 24-105mm. Could do with the hood on, reversed, but getting the lens in/out with the hood attached would be a bit annoying since it'll catch on the edge of the zipper on the chest side when taking the lens out of the pocket. Could probably sew in a piece of material against the zipper's edge and the inside of the pocket to let the hood 'slip' past the zip, or just get in the habit of pushing that zip 'away' from the lens when removing it, though. There's a material lining right up to the edge of the zips on either side, so I don't think there's any risk of scratching the paint on one's lens.
I already see many uses for the vest for my purposes. Filters and holder can go into one of the pockets, film body can easily fit into one of the front pockets without a lens on or into the zipped pockets if the 50mm is attached, 580EX II sized flash on trasceiver+stand fits into one of the zipped pockets if you fold the head down once it's in, can take the transceiver off the camera and stuff it into one of the other pockets while not using it, can use one of the pockets for a second lens, card wallet ought to fit comfortably into the chest pocket (not that I even use my card wallet at the moment, being a single-card shooter) along with some spare batteries...
The only issue for me is that the vest is oversized at the moment, since this is a large.