I'm left handed and own a few lefty bolts. The biggest bore as of right now is a Heym SR 20 classic in 375 H&H. Here's a link to the latest web site. http://www.heym-waffenfabrik.de/english/S_Buechs/S_MagBue/st_MagBu.html
They show almost every caliber made.
Weatherby does a fair job for lefty's. There's a left handed Mauser model 3000L in 375 H&H around on Gunsamerica pretty regularly.
I think if you look around and listen you'll see the left handed world is not as limited as it was years ago.