I know this may sound a little boring, but how about a long throated 300 RUM with a 28-30 inch tube in at least a 9tw, maybe even an 8tw, to shoot some of these new high BC 30 cal bullets. The 200gr SMK has a .715 BC and I bet you could, easily, launch those 3200++ from a 300 RUM. You could easily build it on a factory action with a mag bolt face and with ADG making RUM brass it gives you a source for good quality cases. No special reamer to wait for and off the shelf dies, heck, what's not to like. 
Well what's the fun in that?! 
I know, I know, told you it was a boring idea, but I was trying to appeal to your, please try and hold the laughter to a minimum once you read this, dare I say, practical side. 
Not that I'm particularly old, though some days I wonder, but I find the older I get, the more I appreciate, easy, cartridges. Maybe it would be different if I could shoot right from my home, like some of you lucky basterds do like Jasnt, but since that currently isn't an option, I'd much rather spend more time shooting and less time developing loads.
I still think you need to not give up on the .277 route. Over the years I've talked to a few different guys that had one of Kirby Allen's 270AM which is his version of a 270 RUM and they were very happy with those. Again, a boringly simple cartridge, but a 270RUM or 27 Nosler slinging the 170 Bergers 3300+ would be pretty cool.
It sounds far too useful.
