I've owned such ones as you want, and I don't really recommend them. They aren't as accurate because they weigh much and there is all these buttons, you might hit acidentally during intense gaming and might close down the game or do something that wasn't intended, which just destroys the moment. That is my personal experience, some might have a different experience or opinion in this case.
I would recommend the Steelseries Kinzu, it's cheap and it is the best mouse I've ever held in my hand, it fits perfectly and it is light! You have an option to turn DPI up, you only got 2 settings though, but it's useful when in need in the middle of combat.
"For the price you will have a hard time finding anything better for FPS gaming." - "his mouse should definitely be on your short list if you are a FPS gamer looking for a budget mouse. Since this mouse has a wealthy resolution of up to 3200 DPI and excellent scaling downwards, it can both be the high and low sensitivity gamer's weapon."