Now, finished, done? Okay. Now that is a great post, and makes a lot of excellent, well thought out points, and is generally better game thinking and list building than I am capable of. Can I pirate this list to give more life to the defunct OgrynWing concept? Maybe.
See, a Mortar Team is 2 wounds. A squad of five Ogryn size models, with two wounds each, toting something that looks a bit like a mortar, ought to do the trick. Right? Maybe something like the Leadbelchers above, with a few IG or Space Marine bits to 'tech' them up? Even Ork pieces would not look out of place, if executed properly.
It could work, I think.