As a lefty, I know the pain of trying to find rifles... It is great for people to suggest buying a factory rifle, but in many cases, it is next to impossible to find what you are after in a lefty. I have a beautiful, wood-stocked, Cooper in 300WM. I wanted a synthetic stock, but they don't make them in left handed models.
I wanted a light weight 7mmRM for PA hunting, but that was also very capable for 600+ yards on elk. I figure I saved $1,000-1,500 over the custom builders and I got exactly what I wanted. I ordered the barrel from Hart (#3 fluted, 23" finish length), stock from Manners (EH1, shortened length of pull, flush cups, GAP camo), and had Pierce provide the Ti action, Ti muzzle brake, Timney Calvin Elite trigger, and do the balance of the work. Right now, with a Vortex Razor HD LH on it, it weights 7.75lbs. All in, I have under $5,000 into this rifle (including scope) and it is to my spec, including a custom reamer that I own for loading the Berger 195EOL bullets nice and long. I never intend to sell mine, so resale wasn't a consideration.
My point being, you can get exactly what you want and I think you can do it cheaper than the $6-8K that some of the custom builders charge.
-David