Holland and Holland released the 400 H&H recently within the last year or so. It is based on the .375 H&H case, and is supposed to use a .411" 400 grain bullet at about 2350 fps. Not a wildcat, but there you go.

http://www.african-hunter.com/new_h&h_cartridges.htm

FWIW

tq

Yeah, 404-375 should do better.
Bullet selection is about equal, but with a 400g bullet you'll get a little less SD in trade for a bit lower pressure or higher speed. Same as always: tradeoffs everywhere.

True story. Plus you'd be back in true wildcat territory.

tq