Cat, you are amazing.
Frankly, I like your III-B better than the few pics I've seen of the official ones. Mind you, the "slab-faced" III-B is perfectly fine as is -but yours looks like less of a "kludge" and more like a logical development in hull design for the Ogres.
It does make me wonder what a kit-bash of the III-B would look like using two faces of the MK III instead of the front glacis of a MK V. I suspect it would require a LOT more work as you'd have to trim the two front face-plates of the MK IIIs very closely, then build up some "depth" by adding a stretched rectangle of plastic behind the two MK IIIs to get that "slab" appearance in the image I am thinking about. (Where is that pic, now I'm curious...)
Ah, of course, WH23. (
http://www.warehouse23.com/products/SJG10-0104) I should have remembered that.