Don't we all, AzSteven. I mean....um, how fat exactly? Simply stout, or on the obese side? I think you suggest in your post that it's the latter, in which case....
Reaper have a few. Olaf Gunderson, Dwarf Gambler, definitely has a belly on him, although he looks like something from a western, only with dwarves. Nice, but probably not what you're after. (actually, I took a closer look at him, and he does in fact have a holstered six-shooter!) Kragmarr Pummeler has a good belly, but I wouldn't call him obese. Boren Backslap is stouter than your average Dwarf, and is a lovely miniature, but it's furs and so on, rather than armour. Your best bet might be Gerrin Greystone. The stoutest Reaper dwarf I could find - he has a good belly, scale armour, and an axe and shield. Overall, a very nice miniature. Is it strange that I'm slightly disappointed that there aren't more stout dwarves in the Reaper line?