I am currently also using the deathadder lefthanded and will try out the upcoming ambidextrous Cougar 400m (there is also a thread about it here) . It will be a pretty large mouse, which is rare if it also has to be suited for us lefties. Maybe it's worth a look for you
Here is the link for you:
The only other real option i know to prevent the contact of the hand on the mousepad would be the Razer Ouroboros, which also has side skates and can be adjusted to be very large. It is kinda outdated though and also overpriced.
If you are comfortable with huano-switches (stiffer mouseclicks), the ZA-series from Zowie is also very interesting, at least if you dont mind the crappy scrollwheel. For me, the clicks were too stiff though. It also exceeds your price range.Edited by Nardykil - 10/24/15 at 11:07am