We have been building them from scratch ;-) Much more fun that way and you learn more. 3DRobotics/Pixhawk is where it's at for the hacker minded with good support. If you really want to get in the nity gritty get into MultiWii but expect to be tuning a lot and you give up good GPS support.
30 - 60min Flight times are doable depending on your setup but at that point your payload is almost all battery. Keep in mind weight begets weight.
My local hackers group has also built a 3DR/Pixhawk-based model. Just got an upgraded chassis for it. We're working on an Arduino kit to collect micro-climate data and do some modeling of that. (But also FPV -- everyone wants FPV.)
For higher than 30 minutes you really want to look into planes instead of quadcopters. Running 4/6/8 heavy duty motors forces battery life to be an issue.
A plane has significantly less than that which lets them go for longer.
Good point Skywalker X8 or 1900 are good for longer range FPV planes, I've seen some setups with 80-100km range (UHF Setups) which is pretty impressive.
People have looked at it, but I think the general consensus is that there's not enough surface area on the airframe to generate enough electricity to make a significant impact.
Depending on the exact motor+prop setup, peak draw of between 200-400W is pretty common for fixed wings in the 1.5-2M wingspan range, and cruise is often around half of that.
I get 30 minutes on a HobbyKing Bixler 1.1 with a 5aH battery. I'm using an EzUHF for control with an EzOSD and 1.3Ghz for the video downlink. In a noisy place, like the suburbs of San Antonio, TX I could get 4 miles of range reliably before the video started breaking up. I'm in AK now and have flown to 12 miles with rock-solid video.
Nitpick: Getting started with flying drones would be a better title.
If you are starting with flying drones (quadcopters, airplanes) a visit to an R/C forum will be helpful. There you can learn about many things related to maintaining and operating such machine. Stuff that is usually missing from blog posts because they are old tips & tricks.
30 - 60min Flight times are doable depending on your setup but at that point your payload is almost all battery. Keep in mind weight begets weight.
The Phantom is a toy.