Actually, you have more options than you may have imagined.
The Ruger P-91 (in .40 cal) and the P-90 (in .45 cal) are about as lefty-friendly as they come. They have ambidextrous de-cocking levers and they come with a mag release on both sides of the frame. They still eject to the right though, and many people think the grip is a bit ill-fitting to the hand, but a set of Hogues helps this greatly and there is no doubt they are a sturdy and reliable pistol.
Another option is one of the surplus Walther P.1 or P.38 pistols in 9mm. They eject to the left and the European heel-style mag release is ambidextrous. The decocking lever is on the left side of the frame but most people carry them in DA mode anyway so that issue is pretty moot.
A third completely ambidextrous pistol is the CZ-82, although it's in the Russian 9x18 caliber. It has ambidextrous safeties with mag release buttons on both sides of the frame and, unlike the Ruger, it can be carried either cocked-and-locked or with the hammer down in DA mode. A hard choice to beat for the budget conscious shooter. Cole Distributing is carrying its civilian brother, the CZ-83 in .380 caliber for $220 in 80% condition if the Russian caliber puts you off.
I'm sure there are other options but these are some of the more obvious ones.
-Lee