What kind of holster would be good for a fat guy to carry a conceal carry pistol?  Please no jokes...this is serious business.  Thank you.  [:I]  

It really would depend on what type of weapon, the time of year, and how large of a person you are. Although I don't post, just lurk, yours was one I felt comfortable replying to as I have been carrying in Mi for over 20 years (legally) with various weapons.

Inside the pants holsters are good. Buy a few pairs of jeans one size larger than u usually wear. Thats what I do and I can conceal everything I own shy of a desert eagle. A small but significant plus to us "fat" guys. Forget crossdraws belly gets in the way every time. Small of the back is ok but shirts almost always expose when bending or reaching.
Suspenders help keep pants where I want them so I use them often. Forget wearing dockers/slacks and a gun if you have a large (38+) waist size.
For that senario ankle holster and a small snubby work best for me. As to what brands of holsters you will find that if you are serious about carrying you will acquire a drawer full of holsters of different makes and models until you find an appropriate/favorite rig.

If you have a broadand deep chest to match that big belly [bounce] you may find that certain shoulder holsters work well also, if, you have enough arm length to reach gun.
Be very weary of soft pliable holsters, front sights snag easily.
Learn to wear long cotton undershirts that help protect skin from exposed gun and vice versa.
Learn to buy shirts that fit loosely and that you can wear in casual atmospheres.
Can't help you if you need to be dressed up really nice daily, sorry.
All blued guns should be wiped down daily if you carry, stainless and titanium hold off much better against rust due to sweat and such.
Hope this helped some.