Eh, so, I figured rather than just sit here and twiddle my thumbs thinking about what I might want to do with it, I'd actually make some progress if I impulsively just started banging stuff together which might keep me working on one thing at a time. A beer or two later and some thick styrene, and I've decided to locate the main gun off to one side of the front, since the asymmetry seems a bit more orky.
I really want to build vertically as I move back, so I can give it that 'rolling, armored bunker' look that Forgeworld Battlewagons have. I'm trying to figure out where the weapons might eventually get placed, as well, but it may be the sort of thing that works itself out as I build some more. I feel like a fool, though, since I gave the sponsons away to a buddy of mine thinking I would never need them, and now I find myself wanting to add them all over again. I suppose I'll have to build some fresh ones if I want any on there!