Thanks to everyone for their input and opinions. To close the loop, here's the decision.
I own a P-Ord P14-45 Limited and I own a Beretta 92FS. I like them both. After reading some of your thoughts and suggestions, it occurred to me that maybe a top-end for one of these would give me the best of both worlds ... a gun I already am comfortable with, and the flexibility to change cartridges whenever I want to.
It appears Beretta does not support inter-changeability, unless you buy their 92FS/96 COMBO that features one top end (slide and barrel) in 9mm and another in .40 S&W. To try and do it afterwards is not supported by them. Three seperate dealers have confirmed this. Their loss. (But I still like my 92.)
However, Para-Ordinance very much supports inter-changability. You can purchase a top-end complete, but you must swap out the ejector from the frame whenever you switch from .45 to .40 or vice versa. Other than that, it's just different magazines. The price was very reasonable (in fact, all of their spare parts seem quite reasonably priced), so I have placed the order.
Now it's just waiting .....