Hi Chad,
I agree that Bitcraze made a good choice re: weight/flight time w/ batteries. I too am waiting for mini-reactors!

Regarding your questions, my answers are below.
Did you change out your battery or are you still looking?
I am still looking.
Do you have specific job requirements?
Longer flight-time.
What prompted your look for new battery options?
Great question, my motivation is multifaceted. I love to tinker. Therefore searching for custom modifications comes natural.
Longer flight-time... I've flown gas powered (nitro) helicopters for 10 years, I also fly electric helis and quadcopters. There are trade-offs between the gas & electric RC power plants. One advantage of my gas heli is the extended flight-time (30 minutes). While I enjoy the convenience of electric helis, the nitro side of me prefers longer flight-times.
Putting a larger battery in the Crazy Flie 2 will increase flight-time; however, there is a point where added battery weight diminishes response time or in-flight agility. So, I frequently like to search new batteries to see if they have a better ratio of battery maH to battery weight ratio (grams).