I know Saitek made an ambidexterous stick, dont remember which model (evo maybe?). The only other sticks I know of that are ambidexterous are the CH Flightstick/Flightstick Pro and the CH Gamestick 3D. The Gamestick 3D was analog only, they dont have a USB version of it. You can find it for as low as 10 bucks on the internet now. I use a Flightstick Pro, and while I could wish for more than the 4 buttons, I have no complaints, and it has seen 8 years of service with only 1 minor repair needed. It has a solid feel to it, the base is heavy enough that it doesnt slide around easily, and I love having the manual trim wheels ( I believe on the USB version you can program these to control your elevator and aileron trim tabs as well, dont know for sure as I use the analog version). Plus it has the advantage of being quite a bit smaller on the base than some of the other sticks I've owned, so it's easy to move out of the way when I have work to do.
There might be more out there, but these are the only ones I know of. Hope it helps.