Dakota make a good left hand action and you might also like to consider the Blaser which allows you to change barrels & bolt faces as you like. I think the largest they can cope with is 416 Rigby........but I don't know how much they are in the States.

I'd also say don't worry about recoil too much. If you get the rifle set up properly it won't be a problem. I shoot a .500 Jeffrey and have had a mercury recoil arrestor fitted into the stock and it's almost a pussycat now. If you're looking for a 'client rifle' all you really need to look at are the .375 HH & any of the .416s...... they'll allow you to shoot everything from a duiker to an Elephant (assuming the right bullet choice.

As someone else posted, 'you don't need a charge stopper'. You just need a calibre that will kill big animals and a .375 or .416 will do that.