hoppdoc,
It sounds like you enjoy the idea of hunting with a double so in my opinion a 450/400 would be nice.
I have gone down that track also as I prefer to travel and hunt light and with a double also. I use to hunt with a 9.3 and 470NE which are great, but to travel and hunt with two rifles was not for me so I have on order a searcy 400J with a scope that I can attach when needed.
I know the 470 is a better caliber for elephant but I think the fast double shots of the 400 will be suitable also.
Having a 500 along also will be great for Ele.
ozhunter