I see the .50 Beowulf comes as a four die Lee kit for reloading so that's for sure a straight wall case.

The .405 Win looks good but that and the others seem really limiting in finding a rifle for them. Not saying it couldn't be done but I'm not sure I'm willing to be that limited.

The Rossi .454 does look interesting. I know lots of guys swear the Rossi levers are good stuff if you are willing to tune them a little.